Vinyl alcohol-based polymers and their uses

Abstract

To provide a vinyl alcohol polymer having equivalent properties to vinyl alcohol polymers derived solely from petroleum, thereby conserving petroleum resources and suppressing carbon dioxide emissions during the manufacturing process when using vinyl alcohol polymers (PVA). [Solution] A vinyl alcohol polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), wherein the molar ratio of (A) / (B) is 5 / 95 to 100 / 0.

Description

[Technical Field]

[0001] The present invention relates to a vinyl alcohol polymer obtained by polymerizing and saponifying vinyl acetate synthesized from plant-derived raw materials such as biomass, a slurry additive using the same, drilling mud, cement slurry, a sealant for underground treatment, a multilayer structure with excellent oxygen gas barrier properties, a method for producing the same, and packaging materials, paper coatings, coated paper, seed coating compositions, aqueous emulsions, adhesives, a dispersion stabilizer for suspension polymerization of vinyl compounds, and a dispersion stabilizing aid for suspension polymerization of vinyl compounds. [Background technology]

[0002] Vinyl alcohol polymers (hereinafter sometimes abbreviated as PVA) obtained by polymerizing and saponifying vinyl acetate are among the few crystalline, water-soluble polymers that possess excellent interfacial and strength properties. As a result, they are used in paper processing, textile processing, and as stabilizers for emulsions, and also occupy an important position as PVA-based films and PVA-based fibers.

[0003] Ethylene and acetic acid, the raw materials for vinyl acetate, are produced from fossil resources such as petroleum or natural gas. Specifically, ethylene is produced by mixing hydrocarbons, mainly naphtha, with steam, thermally decomposing them, and then separating the products by distillation. Acetic acid is produced by the carbonylation reaction of methanol, which is obtained by reacting carbon monoxide, produced by the partial oxidation of natural gas, with hydrogen.

[0004] These fossil fuels are at risk of depletion, and there are concerns that their manufacturing process emits carbon dioxide, accelerating global warming.

[0005] By the way, in wells used to extract reserves of oil, natural gas, etc., slurries used for civil engineering and construction, such as drilling cement slurry, have traditionally been used.

[0006] Drilling slurry plays several roles, such as transporting excavated rock fragments and debris, improving the lubrication of bits or drill pipes, filling holes in porous ground, and counteracting reservoir pressure (pressure from the bedrock) caused by hydrostatic pressure. This drilling slurry typically consists mainly of water and bentonite, with the desired performance achieved by adding barite, salt, clay, etc. Such drilling slurry is required to have appropriate flow characteristics, such as temperature stability and not being significantly affected by changes in the concentration of electrolytes (e.g., carboxylates) in the ground. To meet these requirements, it is necessary to adjust the viscosity of the drilling slurry and suppress the dissipation of water contained in the drilling slurry (hereinafter sometimes referred to as "dehydration"). Methods for adjusting the viscosity of drilling slurry and suppressing dehydration are usually employed by adding polymers, such as starch, starch ethers (carboxymethyl starch, etc.), carboxymethylcellulose, carboxymethyl hydroxyethylcellulose, etc.

[0007] However, the addition of these polymers can drastically increase the viscosity of drilling slurry, making it difficult to inject the slurry using pumps. Furthermore, starch and its derivatives do not adequately suppress dehydration in the temperature range above approximately 120°C, and carboxymethylcellulose and carboxymethyl hydroxyethylcellulose do not adequately suppress dehydration in the temperature range of 140°C to 150°C.

[0008] On the other hand, drilling cement slurry is used to fix the casing pipe into the well and protect the inner wall of the well by injecting and hardening it into the tubular void between the geological formation and the casing pipe installed in the well. Generally, the injection of drilling cement slurry into the tubular void is carried out using a pump. Therefore, drilling cement slurry is required to have an extremely low viscosity and not separate in order to facilitate injection by pump.

[0009] However, in the cementing of a shaft, material separation may occur, and moisture may escape through cracks in the shaft, resulting in defects in the cemented part. Therefore, dehydrating reducing agents such as walnut shells, cottonseed, clay minerals, and polymer compounds are added to the drilling cement slurry. Among them, vinyl alcohol-based polymers are well-known dehydrating reducing agents.

[0010] Regarding this dehydrating reducing agent of vinyl alcohol-based polymer, for example, Patent Document 1 discloses a method of using PVA with a saponification degree of 95 mol% or more.

[0011] Patent Document 2 discloses a method of using PVA with a saponification degree of 92 mol% or less.

[0012] Patent Document 3 discloses a method of using PVA with a saponification degree of 99 mol% or more.

[0013] When recovering oil or other underground resources from underground natural resource layers, the problem is that the recovery rate of these resources is low, and various techniques are used to improve this. As a typical technique, there is a method of injecting a fluid into an underground oil field layer for replacement. Fluids such as salt water, fresh water, polymer aqueous solution, and steam are used, and among them, the polymer aqueous solution is useful.

[0014] As an example, a method of injecting steam into an underground shale layer to cause cracks is widely adopted. In this method, first, a vertical hole (vertical shaft) several thousand meters deep underground is drilled vertically with a drill, and when the shale layer is reached, a horizontal hole (horizontal shaft) with a diameter of ten to several tens of centimeters is drilled horizontally. Then, a polymer aqueous solution is injected into the vertical and horizontal shafts to generate cracks (fractures) from the shafts, and natural gas, oil (shale gas - oil), etc. flowing out from the cracks are recovered.

[0015] At this time, in order to make existing cracks grow larger or to generate even more cracks, some of the existing cracks may be temporarily sealed with a ground treatment sealant (additive). By pressurizing the fracturing fluid filled in the well in this state, the fluid can penetrate into other cracks, making existing cracks grow larger and generating new cracks.

[0016] Diverting agents used for underground treatment are used to temporarily seal cracks, as described above. Therefore, they maintain their shape for a certain period while sealing the cracks, and then, when natural gas or oil is extracted, they may be hydrolyzed and disappear or dissolved and removed.

[0017] For example, PVA is used as a sealant for underground treatment, and Patent Document 2 discloses a diverting agent containing PVA.

[0018] Furthermore, Patent Document 3 discloses a diverting agent containing PVA resin particles having a specific particle size.

[0019] Furthermore, Patent Document 4 discloses a ground treatment sealant containing PVA whose swelling rate after immersion in water at 80°C for 30 minutes is within a specific range.

[0020] Multilayer structures with excellent oxygen gas barrier properties are used as packaging materials. Aluminum foil is used as an intermediate layer in such multilayer structures because it has perfect oxygen gas barrier properties. However, when multilayer structures containing aluminum foil are incinerated, residue is produced, and when such multilayer structures are used as packaging materials, the contents cannot be seen, and the contents cannot be inspected with a metal detector.

[0021] Polyvinylidene chloride (hereinafter sometimes abbreviated as "PVDC") has low moisture absorption and good oxygen gas barrier properties even under high humidity, so multilayer structures made by coating various substrates with polyvinylidene chloride are used as packaging materials, etc. Films such as biaxially oriented polypropylene (hereinafter sometimes abbreviated as "OPP"), biaxially oriented nylon (hereinafter sometimes abbreviated as "ON"), biaxially oriented polyethylene terephthalate (hereinafter sometimes abbreviated as "OPET"), and cellophane are used as substrates. However, there was a problem that hydrogen chloride gas was generated when waste of multilayer structures containing PVDC was incinerated.

[0022] For example, Patent Document 5 describes a film containing PVA that contains 3 to 19 mol% of α-olefin units having 4 or fewer carbon atoms. It also states that the film has excellent water resistance and excellent oxygen gas barrier properties even under high humidity conditions.

[0023] Furthermore, it is known that coating paper with PVA can enhance paper strength, improve water resistance and oil resistance, and impart gas barrier properties, and it is widely used. In addition, vinyl alcohol polymers are used as inorganic binders or dispersion stabilizers, and as auxiliary agents for imparting functionality to paper. For example, as an example of using PVA as a paper coating agent, Patent Document 6 discloses an example in which PVA is used as a paper coating agent.

[0024] Seed treatment refers to the application of materials to seeds to improve handling, protect them before germination, and support the germination process. Furthermore, seed treatment can confer pest resistance to seeds or resulting plants by incorporating active "insecticide" components such as insecticides, fungicides, and nematodes. Plant growth regulators that improve seed handling characteristics may also be added to seed coating formulations. Seed treatment eliminates, or at least reduces, the need for traditional broadcast sprays of foliar fungicides or insecticides.

[0025] Unfortunately, many known seed treatments are known to generate excessive dust during the storage and application of seed material, which can lead to bulk seed aggregation and reduce germination efficiency.

[0026] For example, Patent Documents 7 to 20 disclose various and numerous seed coating compositions and components that improve the handling, germination, storage, and growth characteristics of seeds.

[0027] Aqueous seed coating compositions typically include an aqueous medium, one or more functional additives, a binder that forms a matrix for the various functional additives upon drying after application, and a protective film for covering the seeds.

[0028] Some seed treatments incorporate preventative and enhanced treatments, such as those involving pesticides (fungicides and / or insecticides, etc.) in combination with one or more plant inducers and / or inoculants.

[0029] As disclosed in the previously incorporated references, many different materials have been used as binders in aqueous seed coating compositions.

[0030] For example, the binder materials disclosed in Patent Documents 8 to 15 generally include polyvinyl alcohol homopolymers, copolymers, and functionally modified and / or crosslinked versions thereof.

[0031] Some commercially available polymer binders containing certain polyvinyl alcohols suffer from low water solubility / dipole solubility, low coated seed flowability, high levels of dust-off, and / or poor plant properties.

[0032] For example, seed coating additives optimized to reduce dust-off may result in poor seed flowability. This can be explained by the fact that components added to increase the coating's viscosity, which is less susceptible to dusting and typically reduces dust-off, can lead to unacceptable flowability and flatness properties, as this viscosity creates flowability problems.

[0033] On the other hand, factors that increase seed flowability in the coating negatively affect dust-off properties. For mechanical planting, it is essential that the seeds do not clump together. Seeds coated with polymer binders that are not sufficiently hydrophobic will stick together, especially when exposed to warm, humid air, such as that encountered in storage facilities during the summer.

[0034] There is a need for a water-based, biodegradable, and cost-effective seed coating that provides low dust-off properties while improving long-term storage stability and maintaining or even improving seed germination and handling characteristics.

[0035] In addition to its use as a raw material for fibers and films, PVA is widely used as a paper processing agent, fiber processing agent, inorganic binder, adhesive, and stabilizer for emulsion polymerization and suspension polymerization, taking advantage of its water-soluble properties. In particular, PVA is known as a dispersion stabilizer for emulsion polymerization of vinyl ester monomers, such as vinyl acetate. The vinyl ester aqueous emulsion obtained by emulsion polymerization using PVA as a dispersion stabilizer is widely used in various adhesives, including those for woodworking, paint bases, coatings, binders for impregnated paper and nonwoven products, admixtures, jointing materials, paper processing, and fiber processing.

[0036] For example, Patent Document 21 discloses an aqueous emulsion that exhibits excellent high-speed coating properties and initial adhesion.

[0037] Furthermore, Patent Document 22 discloses a woodworking adhesive with excellent water-resistant adhesion by using PVA containing 1 to 10 mol% of ethylene units.

[0038] PVA is commonly used as a dispersant for the suspension polymerization of vinyl chloride. In suspension polymerization, particulate vinyl polymers are obtained by polymerizing vinyl compounds dispersed in an aqueous medium using an oil-soluble catalyst. In this process, a dispersant is added to the aqueous medium to improve the quality of the resulting polymer. Factors that govern the quality of vinyl polymers obtained by suspension polymerization of vinyl compounds include the polymerization rate, the ratio of water to vinyl compounds (monomers), polymerization temperature, the type and amount of oil-soluble catalyst, the type of polymerization vessel, the stirring speed of the contents in the polymerization vessel, and the type of dispersant. Among these, the type of dispersant has a significant impact on the quality of the vinyl polymer, such as the particle size distribution and plasticizer absorption. PVA is used as a dispersant alone or in combination with cellulose derivatives such as PVA, methylcellulose, or carboxymethylcellulose.

[0039] For example, there are cases where PVA is used as a dispersion stabilizer for suspension polymerization. Non-patent document 1 discloses PVA with a degree of polymerization of 2000 and a degree of saponification of 80 mol%, as well as PVA with a degree of polymerization of 700-800 and a degree of saponification of 70 mol%, for use as a dispersant in the suspension polymerization of vinyl chloride.

[0040] Furthermore, Patent Document 23 discloses a dispersant made of PVA having an average degree of polymerization of 500 or more, a ratio of weight-average degree of polymerization Pw to number-average degree of polymerization Pn (Pw / Pn) of 3.0 or less, a structure [-CO-(CH=CH)2] containing a carbonyl group and an adjacent vinylene group, absorbances of 0.3 or more and 0.15 or more at wavelengths of 280 nm and 320 nm for a 0.1% aqueous solution, and a ratio (b) / (a) of absorbance at 320 nm to absorbance at 280 nm (a) of 0.30 or more.

[0041] It has been known for some time that partially saponified vinyl alcohol polymers are used as dispersants for the suspension polymerization of vinyl compounds (e.g., vinyl chloride). However, when ordinary partially saponified PVA is used, it has not always been possible to obtain vinyl resins that meet the performance requirements, specifically (1) high absorption of plasticizers even when used in small amounts, (2) absence of foreign matter such as fish eyes, (3) easy removal of residual monomer components, and (4) minimal formation of coarse particles.

[0042] To satisfy the above performance requirements, methods have been proposed for the suspension polymerization of vinyl compounds, such as using PVA with a low degree of polymerization, a low degree of saponification, and oxyalkylene groups in the side chains (see Patent Documents 24-30), using PVA with ionic groups (see Patent Document 31), and using PVA with alkyl groups at the terminals, preparing an aqueous solution in advance and charging it into the polymerization tank (see Patent Document 32).

[0043] It has been difficult to provide vinyl alcohol polymers that have properties equivalent to or better than those derived solely from petroleum, while also conserving petroleum resources and suppressing carbon dioxide emissions during the manufacturing process. Therefore, in order to reduce the amount of petroleum resources used, it has been considered to change the composition of the resin composition depending on the application, and for example, packaging bags containing biodegradable resin compositions that include biodegradable resins other than petroleum-derived raw materials have been developed (see Patent Document 33). However, in such cases, it is difficult to improve productivity and durability because the tensile strength, tear strength, seal strength, stiffness, and other processability are significantly inferior compared to those of petroleum-based resins (see, for example, paragraph 0004 of Japanese Patent Application Publication No. 2021-14311). [Prior art documents] [Patent Documents]

[0044] [Patent Document 1] Japanese Patent Publication No. 2000-119585 [Patent Document 2] International Publication No. 2019 / 031613 [Patent Document 3] International Publication No. 2019 / 131939 [Patent Document 4] International Publication No. 2019 / 131952 [Patent Document 5] Japanese Patent Publication No. 2000-119585 [Patent Document 6] Japanese Patent Publication No. 2017-43872 [Patent Document 7] U.S. Patent Application Publication No. 3698133 [Patent Document 8] U.S. Patent Application Publication No. 3707807 [Patent Document 9] U.S. Patent Application Publication No. 3947996 [Patent Document 10] U.S. Patent Application Publication No. 4249343 [Patent Document 11] U.S. Patent Application Publication No. 4272417 [Patent Document 12] U.S. Patent Application Publication No. 5849320 [Patent Document 13] U.S. Patent Application Publication No. 5876739 [Patent Document 14] U.S. Patent No. 90101131 [Patent Document 15] International Publication No. 2017 / 187994 [Patent Document 16] U.S. Patent Application Publication No. 4729190 [Patent Document 17] International Publication No. 90 / 11011 [Patent Document 18] International Publication No. 2005 / 062899 [Patent Document 19] International Publication No. 2008 / 037489 [Patent Document 20] International Publication No. 2013 / 166020 [Patent Document 21] Patent No. 6647217 [Patent Document 22] Patent No. 3466316 [Patent Document 23] Special Publication No. 5-88251 [Patent Document 24] Japanese Patent Application Publication No. 9-100301 [Patent Document 25] Japanese Patent Application Publication No. 10-147604 [Patent Document 26] Japanese Patent Application Publication No. 10-259213 [Patent Document 27] Japanese Patent Application Publication No. 11-217413 [Patent Document 28] Japanese Patent Publication No. 2001-040019 [Patent Document 29] Japanese Patent Publication No. 2002-069105 [Patent Document 30] Japanese Patent Publication No. 2007-063369 [Patent Document 31] Japanese Patent Application Publication No. 10-168128 [Patent Document 32] International Publication No. 2015 / 019614 [Patent Document 33] Japanese Patent Publication No. 2009-155516 [Non-patent literature]

[0045] [Non-Patent Document 1] "Poval," published by Polymer Publication Society, 1984, pp. 369-373 and 411. [Overview of the project] [Problems that the invention aims to solve]

[0046] Until now, no vinyl alcohol polymer had been obtained that possessed properties equivalent to or better than those of petroleum-derived vinyl alcohol polymers, while also conserving petroleum resources and suppressing carbon dioxide emissions during the manufacturing process.

[0047] The present invention aims to provide a vinyl alcohol polymer having properties equivalent to or better than those of vinyl alcohol polymers derived solely from petroleum. Furthermore, the present invention aims to provide a vinyl alcohol polymer having properties equivalent to or better than those of vinyl alcohol polymers derived solely from petroleum, thereby conserving petroleum resources and suppressing carbon dioxide emissions during the manufacturing process when using vinyl alcohol polymers (PVA).

[0048] Furthermore, the present invention aims to conserve petroleum resources and suppress carbon dioxide emissions during the manufacturing process when using vinyl alcohol polymers (PVA) in applications such as slurry additives, drilling mud, cement slurry, underground treatment sealants, multilayer structures with excellent oxygen gas barrier properties, methods for producing the same, and packaging materials, paper coatings, coated paper, seed coating compositions, aqueous emulsions, adhesives, dispersion stabilizers for suspension polymerization of vinyl compounds, and dispersion stabilization aids for suspension polymerization of vinyl compounds. Another objective of the present invention is to provide underground treatment sealants containing vinyl alcohol polymers (PVA) that do not have appearance defects. [Means for solving the problem]

[0049] As a result of diligent research, the inventors discovered that the above objective can be achieved by using a vinyl alcohol-based polymer obtained by polymerizing and saponifying a vinyl ester monomer, which is partly derived from a plant, and thus arrived at the present invention.

[0050] In other words, it encompasses the following inventions. [1] A vinyl alcohol polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), wherein the molar ratio of (A) / (B) is 5 / 95 to 100 / 0. [2] The vinyl alcohol polymer (X) according to [1], further comprising ethylene units, wherein the content of ethylene units is 1 mol% or more and less than 20 mol%. A slurry additive comprising the vinyl alcohol polymer (X) described in [3][1] or [2]. Drilling slurry containing the slurry additives described in [4][3]. [5] The drilling slurry according to [4], further comprising water and bentonite. A cement slurry containing the slurry additive described in [6][3]. [7] The cement slurry according to [6] further comprising a liquid agent and a hardening powder. [8] [1] or [2] contains a vinyl alcohol polymer (X) as described above. A ground filler for underground treatment, with a molar ratio of (A) / (B) of 5 / 95 to 90 / 10. [9] The underground treatment sealant according to [8], wherein the vinyl alcohol polymer (X) comprises another unsaturated monomer (C) copolymerizable with a vinyl ester monomer.

[10] Furthermore, a soil treatment sealant according to [8] or [9], comprising a plasticizer. The material has a layer (C) containing a vinyl alcohol polymer (X) as described in

[11] [1] or [2], and a layer (D) containing a resin. A multilayer structure in which the resin is at least one resin selected from the group consisting of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride (PVC) resin, ABS resin, polylactic acid (PLA) resin, polybutylene succinate (PBS) resin, polyhydroxyalkanoate (PHA) resin, polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin, starch, and cellulose.

[12] The method comprises the steps of preparing an aqueous solution containing the vinyl alcohol polymer (X) to obtain a coating agent, and applying the coating agent to the surface of a resin-containing substrate. The method for producing a multilayer structure according to

[11] , wherein the resin is at least one resin selected from the group consisting of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride (PVC) resin, ABS resin, polylactic acid (PLA) resin, polybutylene succinate (PBS) resin, polyhydroxyalkanoate (PHA) resin, polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin, starch, and cellulose. A packaging material comprising the multilayer structure described in

[13]

[11] . A paper coating agent comprising the vinyl alcohol polymer (X) described in

[14] [1] or [2]. Coated paper, wherein the paper coating agent described in

[15]

[14] is applied to paper.

[16] The coated paper described in

[15] , which is a release paper base.

[17] Oil-resistant paper, the coated paper described in

[15] . A seed coating composition comprising the vinyl alcohol polymer (X) described in

[18] [1] or [2].

[19] The seed coating composition according to

[18] further comprising one or more hydrophobic pesticides.

[20] An aqueous emulsion comprising a dispersant and a dispersed phase, The dispersed phase comprises a polymer (Y1) containing ethylenically unsaturated monomer units, An aqueous emulsion wherein the dispersant comprises the vinyl alcohol polymer (X) described in [1] or [2].

[21] The aqueous emulsion according to

[20] , wherein the polymer (Y1) containing ethylenically unsaturated monomer units is a polymer having specific units derived from at least one selected from the group consisting of vinyl ester monomers, (meth)acrylic acid ester monomers, styrene monomers and diene monomers, and the content of the aforementioned units relative to the total monomer units of the polymer is 70% by mass or more.

[22] The aqueous emulsion according to

[20] or

[21] , further comprising a polyvalent isocyanate compound. An adhesive containing an aqueous emulsion as described in any of

[23]

[20] to

[22] . A dispersion stabilizer for suspension polymerization of vinyl compounds, containing a vinyl alcohol polymer (X) as described in

[24] [1] or [2]. A method for producing a vinyl resin, comprising the step of carrying out suspension polymerization of a vinyl compound in the presence of a suspension polymerization dispersion stabilizer described in

[25]

[24] .

[26] The process includes carrying out suspension polymerization of a vinyl compound in the presence of the aforementioned suspension polymerization dispersion stabilizer and a further dispersion stabilization aid, The method for producing a vinyl resin according to

[25] , wherein the dispersion stabilizing agent comprises a vinyl alcohol-based polymer (Y2) having a degree of saponification of less than 65 mol%.

[27] [1] or [2] contains a vinyl alcohol polymer (X) as described above. A dispersion stabilizer for suspension polymerization of vinyl compounds, wherein the degree of saponification of the vinyl alcohol polymer (X) is 20 mol% or more and less than 60 mol%. The process includes carrying out suspension polymerization of a vinyl compound in the presence of the suspension polymerization dispersion stabilizer described in

[28]

[27] and the suspension polymerization dispersion stabilizer, A method for producing a vinyl resin, wherein the aforementioned dispersion stabilizer for suspension polymerization contains a vinyl alcohol-based polymer (Y3) with a degree of saponification of 65 mol% or more and a viscosity-average degree of polymerization of 600 or more.

[29] The method for producing a vinyl resin according to

[28] , wherein the mass ratio of the dispersion stabilizer to the dispersion stabilizing aid (dispersion stabilizer / dispersion stabilizing aid) is 95 / 5 to 20 / 80. [Effects of the Invention]

[0051] According to the present invention, by using plant-derived PVA as a portion of the PVA, it is possible to provide a vinyl alcohol polymer having properties equivalent to or better than those of vinyl alcohol polymers derived solely from petroleum. Therefore, according to the present invention, petroleum resources can be conserved, and carbon dioxide emissions during the manufacturing process can be reduced, thereby mitigating global warming.

[0052] Furthermore, according to the present invention, by using plant-derived PVA for a portion of the PVA used in slurry additives, drilling mud, cement slurry, underground treatment sealants, multilayer structures with excellent oxygen gas barrier properties, methods for producing the same, and packaging materials, paper coatings, aqueous emulsions, adhesives, seed coating compositions, dispersion stabilizers for suspension polymerization of vinyl compounds, and dispersion stabilizing aids for suspension polymerization of vinyl compounds, petroleum resources can be conserved, and carbon dioxide emissions during the manufacturing process can be reduced, thereby mitigating global warming.

[0053] Furthermore, the present invention provides a sealant for underground treatment containing a vinyl alcohol polymer (PVA) that does not have appearance defects. Also, the present invention provides a multilayer structure with excellent gas barrier properties under high humidity conditions, and a packaging material comprising the same. [Modes for carrying out the invention]

[0054] The following describes embodiments for carrying out the present invention.

[0055] [Vinyl alcohol polymer (X)] The vinyl alcohol polymer (X) of the present invention is a vinyl alcohol polymer (X) (hereinafter sometimes abbreviated as PVA(X)) obtained by polymerizing a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B) and saponifying them, wherein the molar ratio of (A) / (B) is 5 / 95 to 100 / 0.

[0056] Plant-derived vinyl ester monomer (A) (hereinafter also simply referred to as "vinyl ester monomer (A)") refers to a material derived from biomass (non-fossil raw materials), and specifically refers to a vinyl ester monomer (preferably vinyl acetate) obtained by reacting ethylene (hereinafter also referred to as bioethylene) obtained from plant raw materials such as sugarcane and corn with a lower carboxylic acid such as acetic acid. Biomass can be a single non-fossil raw material or a mixture of non-fossil raw materials. Examples include cellulosic crops (pulp, kenaf, wheat straw, rice straw, waste paper, papermaking residues, etc.), wood, charcoal, compost, natural rubber, cotton, sugarcane, okara (soybean pulp), oils and fats (rapeseed oil, cottonseed oil, soybean oil, coconut oil, castor oil, etc.), carbohydrate crops (corn, potatoes, wheat, rice, rice husks, rice bran, old rice, cassava, sago palm, etc.), bagasse, buckwheat, soybeans, essential oils (pine root oil, orange oil, eucalyptus oil, etc.), pulp black liquor, and vegetable oil residue. Furthermore, biomass is not limited to biofuel harvests, but can also include agricultural residues, municipal waste, industrial waste, papermaking sediments, pasture waste, and wood and forest waste. More specifically, as an example, raw sugar and molasses are separated by centrifugation after heating and concentrating sugar solutions extracted from sugarcane and corn to crystallize them. The molasses is then diluted with water to an appropriate concentration and fermented with yeast to produce ethanol (bioethanol). This bioethanol is then heated and ethylene is obtained through an intramolecular dehydration reaction in the presence of a catalyst. In another example, ethanol (bioethanol) is produced by treating pulp black liquor with acid or enzymes, and ethylene is obtained similarly. On the other hand, petroleum-derived vinyl ester monomer (B) (hereinafter also simply referred to as "vinyl ester monomer (B)") refers to vinyl ester monomers obtained using ethylene derived from naphtha, which is normally obtained, as a raw material.

[0057] PVA(X) is synthesized by saponifying a vinyl ester polymer obtained by polymerizing a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B).

[0058] Examples of polymerization methods for vinyl ester monomers include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and dispersion polymerization. From an industrial standpoint, solution polymerization, emulsion polymerization, or dispersion polymerization are preferred. The polymerization of vinyl ester monomers may be carried out using batch, semi-batch, or continuous polymerization methods.

[0059] Examples of vinyl ester monomers (vinyl ester monomer (A) and vinyl ester monomer (B)) include vinyl acetate, vinyl formate, vinyl propionate, vinyl caprylate, vinyl versatate, etc., and among these, vinyl acetate is preferred from an industrial standpoint. Vinyl ester monomer (A) and vinyl ester monomer (B) may be the same compound (e.g., vinyl acetate) or different compounds. That is, PVA(X) may be a homopolymer of one type of vinyl ester monomer or a copolymer of different vinyl ester monomers.

[0060] Polymerization initiators used in polymerization are selected from known polymerization initiators, such as azo initiators, peroxide initiators, and redox initiators, depending on the polymerization method. Examples of azo initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). Examples of peroxide initiators include peroxydicarbonate compounds such as diisopropyl peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, and diethoxyethyl peroxydicarbonate; perester compounds such as t-butylperoxyneodecanate and α-cumylperoxyneodecanate; acetylcyclohexylsulfonyl peroxide; and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate. Potassium persulfate, ammonium persulfate, hydrogen peroxide, etc., may be combined with the above initiators to form polymerization initiators. Redox initiators are polymerization initiators that combine, for example, the above peroxide-based initiators or oxidizing agents (potassium persulfate, ammonium persulfate, hydrogen peroxide, etc.) with reducing agents such as sodium bisulfite, sodium bicarbonate, tartaric acid, L-ascorbic acid, and rongalit. The amount of polymerization initiator used varies depending on the polymerization catalyst and cannot be determined in general terms, but it is selected according to the polymerization rate.

[0061] Furthermore, PVA(X) may be a vinyl ester copolymer obtained by copolymerizing a vinyl ester monomer (vinyl ester monomer (A) and vinyl ester monomer (B)) with another unsaturated monomer that can copolymerize, to the extent that it does not impair the spirit of the present invention, and which has been saponified.Other unsaturated monomers include, for example, α-olefins such as ethylene, propylene, n-butene, and isobutylene; acrylic acid and its salts; acrylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; methacrylic acid and its salts; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, Methacrylic acid esters such as i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate; acrylamide; N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts or its quaternary salts, N-methylolacrylamide Examples include acrylamide derivatives such as methacrylamide and its derivatives; methacrylamide; methacrylamide derivatives such as N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and its salts, methacrylamidepropyldimethylamine and its salts or quaternary salts, N-methylolmethacrylamide and its derivatives; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, and stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinylides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid and their salts or mono or dialkyl esters; vinylsilyl compounds such as vinyltrimethoxysilane; and isopropenyl acetate. Of these, one or more can be copolymerized. PVA having such copolymerization components is sometimes called "modified PVA."

[0062] Ethylene is particularly preferred as another unsaturated monomer that copolymerizes with the vinyl ester monomer. That is, PVA(X) may preferably further contain ethylene units. When PVA(X) further contains ethylene units, the lower limit of the ethylene unit content may be greater than 0 mol%, and may be 0.1 mol% or more. The ethylene unit content is preferably 1 mol% or more and less than 20 mol%. More preferably the ethylene unit content is 1.5 mol% or more, and even more preferably 2 mol% or more. On the other hand, the ethylene unit content is preferably 15 mol% or less, more preferably 10 mol% or less, and even more preferably 8.5 mol% or less. When ethylene is used as a copolymerizing component, the ethylene may be produced from ordinary petroleum-derived raw materials, from the above-mentioned bioethanol as a raw material, or a mixture of both.

[0063] In applications as a slurry additive, drilling mud, and cement slurry, PVA(X) is particularly preferred when vinyl ester monomer (A) and vinyl ester monomer (B) are copolymerized with ethylene. By copolymerizing vinyl ester with ethylene, the solubility of PVA(X) after saponification can be reduced. This further suppresses dewatering from the slurry at high temperatures and the increase in slurry viscosity.

[0064] Regarding the ethylene unit content of PVA(X), it is preferable that it be less than 10 mol%, more preferably less than 9 mol%, and even more preferably less than 8 mol% of the total structural units of PVA(X), in order to have properties equivalent to or better than petroleum-derived vinyl alcohol polymers in applications as slurry additives, drilling mud, and cement slurry. When PVA(X) is a copolymer that contains ethylene units as constituent units, the lower limit of the ethylene unit content may be greater than 0 mol%, may be 0.1 mol% or more, or may be 1 mol% or more.

[0065] The ethylene unit content of PVA(X) is the vinyl ester polymer, which is the precursor of PVA(X).1 The values ​​were determined from 1H-NMR. Specifically, the precursor vinyl ester polymer was thoroughly reprecipitated at least three times using a mixed solution of n-hexane and acetone, and then dried under reduced pressure at 80°C for three days to prepare the vinyl ester polymer for analysis. This vinyl ester polymer was dissolved in DMSO-d6 and subjected to 500 MHz 1 Measurements were taken at 80°C using 1H-NMR (JEOL GX-500). The ethylene unit content was calculated using the peak derived from the main chain methine of the vinyl ester (integral value P: 4.7 ppm to 5.2 ppm) and the peak derived from the main chain methylene of ethylene, vinyl ester, and the third component (integral value Q: 0.8 ppm to 1.6 ppm). Ethylene unit content (mol %) = 100 × ((Q-2P) / 4) / P

[0066] As described above, PVA(X) can be copolymerized with other unsaturated monomers copolymerizable with vinyl ester monomers. PVA(X) obtained by copolymerizing with unsaturated monomers such as unsaturated monocarboxylic acids, unsaturated dicarboxylic acids or their salts, or their mono or dialkyl esters, has a carboxylic acid-containing structural unit, and is therefore preferable in that it dissolves more appropriately and has a lower environmental impact when used as a sealant for underground treatment, a paper coating agent, a seed coating composition, or a dispersion stabilizer for suspension polymerization of vinyl compounds.

[0067] In applications such as a sealant for underground treatment, a paper coating agent, a seed coating composition, and a dispersion stabilizer for suspension polymerization of vinyl compounds, when PVA(X) is modified PVA, the modification rate of such modified PVA, i.e., the content of structural units derived from "other unsaturated monomers copolymerizable with vinyl ester monomers" relative to the total structural units constituting the modified PVA, is preferably 0.5 mol% to 10 mol%, more preferably 0.7 mol% to 8 mol%, and even more preferably 1.0 mol% to 5 mol%.

[0068] Furthermore, the modification rate in modified PVA is the same as that of a PVA-based resin with a saponification degree of 100 mol%. 1The denaturation rate can be determined from the 1H-NMR spectrum (solvent: DMSO-d6, internal standard: tetramethylsilane). Specifically, the denaturation rate can be calculated from the peak areas derived from the protons of the hydroxyl group in the denaturing group, methine protons, and methylene protons, as well as the methylene protons of the main chain and the protons of the hydroxyl group linked to the main chain.

[0069] Ethylene is particularly preferred as another unsaturated monomer that copolymerizes with vinyl ester monomers in applications such as paper coatings, multilayer structures and packaging materials using the same, aqueous emulsions and adhesives using the same. The ethylene unit content in PVA(X) containing ethylene units is preferably 1 mol% or more and less than 20 mol%. When the ethylene unit content is 1 mol% or more, the resulting PVA(X) has better gas barrier properties. The ethylene unit content is more preferably 1.5 mol% or more, and even more preferably 2 mol% or more. On the other hand, when the ethylene unit content is less than 20 mol%, PVA(X) has appropriate water solubility and is easy to prepare as an aqueous solution. The ethylene unit content is preferably 15 mol% or less, more preferably 10 mol% or less, and even more preferably 8.5 mol% or less. When ethylene is used as a copolymerizing component, the ethylene may be produced from ordinary petroleum-derived raw materials, from the above-mentioned bioethanol as a raw material, or a mixture of both. If PVA(X) is a copolymer containing ethylene units as constituent units, the lower limit of the ethylene unit content may be greater than 0 mol%, may be 0.1 mol% or more, or may be 1 mol% or more.

[0070] When polymerizing vinyl ester monomer (A) and vinyl ester monomer (B), a chain transfer agent may be present to adjust the degree of polymerization of PVA(X), etc. Examples of chain transfer agents include aldehydes such as acetaldehyde, propionaldehyde, butyraldehyde, and benzaldehyde; ketones such as acetone, methyl ethyl ketone, hexanone, and cyclohexanone; mercaptans such as 2-hydroxyethanethiol; thiocarboxylic acids such as 3-mercaptopropionic acid and thioacetic acid; and halogenated hydrocarbons such as trichloroethylene and perchloroethylene, with aldehydes or ketones being preferred. The amount of chain transfer agent added should be determined according to the chain transfer constant of the chain transfer agent, the degree of polymerization of PVA to be achieved, etc.

[0071] For the saponification reaction of vinyl ester polymers, alcohol decomposition or hydrolysis reactions using known basic catalysts such as sodium hydroxide, potassium hydroxide, or sodium methoxide, or acidic catalysts such as p-toluenesulfonic acid, can be applied.

[0072] Solvents used in saponification reactions include alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; and aromatic hydrocarbons such as benzene and toluene. These may be used individually or in combination of two or more. In particular, it is convenient and preferable to use methanol or a mixed solution of methanol and methyl acetate as the solvent and carry out the saponification reaction in the presence of sodium hydroxide, which is a basic catalyst.

[0073] (Degree of saponification) For use as a slurry additive, in drilling mud, and in cement slurry, the degree of saponification of PVA(X) is preferably 99 mol% or higher, and more preferably 99.5 mol% or higher. PVA is a crystalline polymer having crystalline portions due to hydrogen bonding of the hydroxyl groups it contains. The degree of crystallinity of PVA(X) improves with increasing degree of saponification, and this improvement in crystallinity reduces the water solubility of PVA(X). In particular, the solubility of PVA(X) in high-temperature water changes significantly at a saponification degree of 99.5 mol%. Therefore, PVA(X) with a saponification degree of 99.5 mol% or higher has high water resistance (low solubility) due to the strength of its hydrogen bonding, and may have water resistance comparable to PVA(X) with chemical crosslinking. Therefore, by having a saponification degree of 99.5 mol% or higher for PVA(X), it is possible to suppress dewatering and viscosity increase of the slurry even with PVA(X) that has not undergone chemical crosslinking, and as a result, it is cost-effective because the chemical crosslinking process can be omitted. In particular, when used as an additive for cement slurry, a low degree of saponification may not adequately suppress dewatering at high temperatures.

[0074] The degree of saponification of PVA(X) was measured according to JIS K 6726:1994.

[0075] In applications as a sealant for underground treatment and a paper coating agent, the degree of saponification of PVA(X) is preferably 90 mol% or more, more preferably 98 mol% or more, even more preferably 99 mol% or more, and particularly preferably 99.5 mol% or more. PVA is a crystalline polymer having crystalline portions due to hydrogen bonding of the hydroxyl groups it contains. The degree of crystallinity of PVA(X) improves with increasing degree of saponification, and this improvement in crystallinity reduces the water solubility of PVA(X).

[0076] In applications of multilayer structures and packaging materials using the same, there are no particular restrictions on the degree of saponification of PVA(X), but it is preferably 80 to 99.99 mol%. When the degree of saponification is 80 mol% or higher, the oxygen gas barrier properties of the resulting multilayer structure are superior. The degree of saponification is more preferably 85 mol% or higher, and even more preferably 90 mol% or higher. On the other hand, when the degree of saponification is 99.99 mol% or lower, PVA(X) can be produced stably. The degree of saponification is more preferably 99.5 mol% or lower, even more preferably 99 mol% or lower, and particularly preferably 98.5 mol% or lower.

[0077] In applications of seed coating compositions, the degree of saponification of PVA(X) is preferably 65 mol% or more, more preferably 67 mol% or more, even more preferably 69 mol% or more, and particularly preferably 70 mol% or more. When the degree of saponification of PVA(X) is 60 mol% or more, the water solubility of PVA(X) is better, which is more advantageous in the manufacture of seed coating compositions.

[0078] In applications of aqueous emulsions and adhesives using the same, there are no particular restrictions on the degree of saponification of PVA(X), but 80 to 99.99 mol% is preferred. A degree of saponification of 80 mol% or higher can further suppress the aggregation of aqueous emulsion particles during storage, potentially improving stability. More preferably, the degree of saponification is 82 mol% or higher, and even more preferably 85 mol% or higher. On the other hand, a degree of saponification of 99.99 mol% or lower tends to further stabilize the aqueous emulsion particles, making manufacturing easier. More preferably, the degree of saponification is 99.5 mol% or lower, even more preferably 99 mol% or lower, and particularly preferably 98.5 mol% or lower.

[0079] In applications as a dispersion stabilizer for suspension polymerization of vinyl compounds, the degree of saponification of PVA(X) is preferably 60 mol% to 99.5 mol%, more preferably 65 mol% to 99.2 mol%, and even more preferably 68 mol% to 99.0 mol%. When the degree of saponification is 60 mol% or higher, PVA(X) has excellent water solubility, making it easy to prepare an aqueous solution of the dispersion stabilizer. On the other hand, when the degree of saponification is 99.5 mol% or lower, the formation of a large amount of coarse particles can be further suppressed when suspension polymerization is carried out using the resulting dispersant. In addition, the resulting vinyl polymer particles may have high porosity and excellent plasticizer absorption.

[0080] In its use as a dispersion stabilizing agent for suspension polymerization of vinyl compounds, the degree of saponification of PVA(X) is 20 mol% or more and less than 60 mol%, preferably 25 mol% or more and 58 mol%, and more preferably 30 mol% or more and 56 mol%. If the degree of saponification is 20 mol% or less, it is difficult to produce PVA(X). On the other hand, if the degree of saponification is 60 mol% or more, it may become difficult to remove monomer components from vinyl polymer particles obtained by suspension polymerization of vinyl compounds, or the plasticizer absorption of the resulting vinyl polymer particles may decrease.

[0081] (Degree of polymerization) For use as a slurry additive, in drilling mud, and in cement slurry, the degree of polymerization of PVA(X) is preferably 1,500 to 4,500, and more preferably 2,000 to 3,800. When the degree of polymerization of PVA(X) is 4,500 or less, an appropriate viscosity can be obtained even at high temperatures when PVA(X) is used as a cement slurry additive. On the other hand, when the degree of polymerization of PVA(X) is 1,500 or more, dewatering can be sufficiently suppressed even at high temperatures.

[0082] In applications as a sealant for underground treatment, a paper coating agent, a seed coating composition, and a dispersion stabilizer for suspension polymerization of vinyl compounds, the degree of polymerization of PVA(X) is preferably 150 to 5,000, more preferably 300 to 4,000, and even more preferably 500 to 3,500. When the degree of polymerization of PVA(X) is 5,000 or less, it is industrially advantageous in terms of the manufacturability of PVA(X). On the other hand, in applications as a sealant for underground treatment, a degree of polymerization of PVA(X) of 150 or more provides a more appropriate sealing effect. Furthermore, in applications as a paper coating agent, a degree of polymerization of PVA(X) of 150 or more allows for the application of appropriate water resistance to the coated paper. In applications as a seed coating composition, a degree of polymerization of PVA(X) of 150 or more provides superior coating effects. A degree of polymerization of PVA(X) of 150 or higher is advantageous in the manufacturing of PVA(X) and provides superior performance as a dispersion stabilizer for suspension polymerization.

[0083] In applications of multilayer structures and packaging materials using the same, the degree of polymerization of PVA(X) is preferably 150 to 5,000, more preferably 200 to 5,000. When the degree of polymerization of PVA(X) is 150 or higher, it is more advantageous in the manufacture of the multilayer structure. The degree of polymerization is more preferably 250 or higher, even more preferably 300 or higher, and particularly preferably 400 or higher. On the other hand, when the degree of polymerization of PVA(X) is 5,000 or lower, the viscosity of the aqueous solution does not become too high, and handling is improved. The degree of polymerization of PVA(X) is more preferably 4,500 or lower, even more preferably 4,000 or lower, and particularly preferably 3,500 or lower.

[0084] In applications as a paper coating agent, the degree of polymerization of PVA(X) is preferably 150 to 5,000, and more preferably 300 to 4,000. A degree of polymerization of 5,000 or less is more advantageous in terms of PVA(X) production. On the other hand, a degree of polymerization of 150 or more allows for the application of appropriate water resistance to the coated paper.

[0085] In applications of aqueous emulsions and adhesives using the same, the degree of polymerization of PVA(X) is preferably 150 to 5,000, more preferably 200 to 5,000. When the degree of polymerization of PVA(X) is 150 or higher, the storage stability of the resulting aqueous emulsion can be improved. The degree of polymerization is more preferably 250 or higher, even more preferably 300 or higher, and particularly preferably 400 or higher. On the other hand, when the degree of polymerization of PVA(X) is 5,000 or lower, the viscosity of the aqueous solution does not become too high, and handling can be improved. The degree of polymerization of PVA(X) is more preferably 4,500 or lower, even more preferably 4,000 or lower, and particularly preferably 3,500 or lower.

[0086] In its application as a dispersion stabilizing agent for the suspension polymerization of vinyl compounds, the degree of polymerization of PVA(X) is preferably 100 to 700, more preferably 120 to 650, and even more preferably 150 to 600. When the degree of polymerization of PVA(X) is 700 or less, monomer components can be more easily removed from vinyl polymer particles obtained by the suspension polymerization of vinyl compounds, the plasticizer absorption of the resulting vinyl polymer particles is improved, and the viscosity can be suppressed from becoming extremely high when provided as a high-concentration aqueous dispersion stabilizing agent solution, resulting in excellent handling properties. On the other hand, when the degree of polymerization of PVA(X) is 100 or more, it is more advantageous in terms of PVA(X) production.

[0087] The degree of polymerization (viscosity-average degree of polymerization) of PVA(X) is a value measured in accordance with JIS K 6726:1994. That is, the degree of polymerization of PVA can be determined from the intrinsic viscosity [η] (dL / g) measured in water at 30°C using the following formula. Degree of polymerization = ([η]×1000 / 8.29) (1 / 0.62)

[0088] In the present invention, the molar ratio (A) / (B) of plant-derived vinyl ester monomer (A) to petroleum-derived vinyl ester monomer (B) in the vinyl alcohol polymer (X) is 5 / 95 to 100 / 0, which is advantageous in terms of obtaining the desired effect. The molar ratio (A) / (B) can be set arbitrarily, but when the ratio of (A) is 5 / 95 or higher in the (A) / (B) ratio, it has properties equivalent to or better than a vinyl alcohol polymer derived solely from petroleum, fully utilizes plant-derived raw materials, and has a greater effect in reducing environmental impact. From the above viewpoint, the lower limit of the ratio of plant-derived vinyl ester monomer (A) is more preferably 10 / 90 in the molar ratio (A) / (B), even more preferably 20 / 80, and even more preferably 25 / 75. Furthermore, the upper limit of the ratio of plant-derived vinyl ester monomer (A) is preferably 90 / 10 in molar ratio (A) / (B), more preferably 80 / 20, even more preferably 70 / 30, particularly preferably 60 / 40, and most preferably 50 / 50, considering the balance between environmental impact and raw material costs. When the upper limit of the ratio of plant-derived vinyl ester monomer (A) is set to the above values, problems such as appearance defects like cracking in the resulting PVA(X) are less likely to occur, which is advantageous in terms of manufacturing.

[0089] (Biomass content) In this invention, biomass-derived carbon refers to carbon that was previously present in the atmosphere as carbon dioxide, was incorporated into plants, and is present in organic matter synthesized using these plants as raw materials. This can be identified by measuring radioactive carbon (i.e., carbon-14). Furthermore, the proportion of biomass-derived components can be determined by measuring radioactive carbon (carbon-14). Specifically, since fossil raw materials such as petroleum contain almost no carbon-14 atoms, the proportion of biomass-derived carbon in the sample can be determined by measuring the concentration of carbon-14 in the target sample and working backward using the atmospheric carbon-14 content (107 pMC (percent Modern Carbon)) as an indicator.

[0090] The proportion of biomass-derived carbon determined by such radiocarbon measurements can be obtained, for example, by subjecting a sample (vinyl ester) to carbon dioxide or graphite as necessary and then comparatively measuring the carbon-14 content with respect to a reference material (e.g., NIST oxalic acid in the United States) by accelerator mass spectrometry (AMS method; Accelerator Mass Spectrometry). The content ratio (%) of biomass-derived carbon can be calculated by [(amount of biomass-derived carbon in the sample) / (total amount of carbon in the sample) × 100].

[0091] The ratio of non-fossil raw materials to fossil raw materials of the vinyl ester monomer is as described above 14 can be determined by measuring C / C and can be distinguished from vinyl ester monomers obtained from ethylene derived from petroleum.

[0092] When ethylene derived from biomass (non-fossil raw material) is used as part of the raw material of the vinyl ester monomer, the ratio of non-fossil raw material of the vinyl ester monomer is the 14 C (radiocarbon) / C (carbon). In vinyl ester monomers obtained from fossil raw materials 14 C / C is less than 1.0×10 -14 whereas the vinyl ester monomer (A) used in the present invention 14 C / C is preferably 1.0×10 -14 or more, more preferably 1.0×10 -13 or more, and even more preferably 1.0×10 -12 . For example, it can be obtained by comparatively measuring the content of carbon-14 ( 14 C) in oxalic acid, which is a reference material prepared by the National Institute of Standards and Technology in the United States. By analyzing such 14 C / C amount, the non-fossil raw material ratio in the vinyl ester monomer can be measured.

[0093] Since artificially produced 14 C generated by nuclear tests in the atmosphere exists naturally, 14The C concentration may be slightly higher than the standard level, and sometimes the pMC may reach over 100%, but this can be corrected as needed to determine the ratio of non-fossil to fossil raw materials. 14 The half-life of carbon is 5,730 years, but considering the time it takes for common chemical products, especially vinyl acetate, and vinyl acetate resins and their saponified products, to reach the market after manufacturing, 14 The decrease in the amount of C is negligible. Furthermore, in this invention, 14 C / C is 1.0 × 10 -14 In such cases, it can be appropriately replaced with pMC (Modern Carbon-to-Minimum Carbon) in the notation.

[0094] The PVA(X) of this invention has a biomass content of 5-90%. Measuring this biomass content can be useful for traceability of carbon raw materials in products.

[0095] Furthermore, if PVA(X) contains copolymer components such as ethylene, it is expressed as the biomass content including those copolymer components. However, the non-fossil raw material content as vinyl ester monomers can be calculated from the raw material properties and modification rate of the copolymer components.

[0096] [Additives for slurry] The slurry additive of the present invention contains a vinyl alcohol-based polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 100 / 0. Furthermore, the drilling mud of the present invention contains a vinyl alcohol-based polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 100 / 0. In addition, the cement slurry of the present invention contains the slurry additive.

[0097] The slurry additive of the present invention can be used as an additive for drilling mud slurry and cement slurry. The slurry additive contains the above-mentioned PVA(X). This PVA(X) is contained in the slurry additive in powder form (hereinafter, such powdered PVA(X) is also referred to as "PVA powder"). The slurry additive may contain only PVA powder, or it may contain PVA powder in addition to other optional components. The PVA powder content in the slurry additive is, for example, 50% by mass or more and 100% by mass or less, preferably 80% by mass or more and 100% by mass or less.

[0098] The particle size of the PVA powder is preferably such that it can pass through a sieve with a nominal mesh size of 1.00 mm (16 mesh). When such PVA powder is included as an additive in slurries such as drilling mud or cement slurry, it becomes easier to suppress dewatering from the slurry at high temperatures. On the other hand, the lower limit of the particle size of the PVA powder is within a range where the solubility does not become extremely large, and it is preferably a size that does not pass through a nominal mesh size of 45 μm (325 mesh), and more preferably a size that does not pass through a nominal mesh size of 53 μm (280 mesh).

[0099] [Drilling slurry] The drilling slurry of the present invention serves roles such as transporting excavated rock fragments and drilling debris, improving the lubrication of bits and drill pipes, filling holes in porous ground, and counteracting reservoir pressure (pressure from the bedrock) caused by hydrostatic pressure. This drilling slurry contains the slurry additive and is mainly composed of water and mud. The drilling slurry may contain optional components as long as they do not impair the effects of the present invention.

[0100] The drilling slurry of the present invention contains PVA(X). A preferred embodiment is a drilling slurry containing PVA(X), water, and mud. Such a drilling slurry is produced by mixing mud, water, and the slurry additive. Specifically, the drilling slurry can be produced by using a water-clay suspension, in which mud is dispersed and suspended in water, as a base, and adding the slurry additive and, if necessary, optional components.

[0101] <Additive for drilling slurry> One preferred embodiment is drilling slurry containing an additive for drilling slurry. The additive for drilling slurry contains the PVA powder described above. Alternatively, the additive for drilling slurry may contain only PVA powder. Another preferred embodiment is drilling slurry containing PVA(X), water, and bentonite. PVA(X) and PVA powder have been described above, so a redundant explanation is omitted here.

[0102] However, in the drilling slurry, the particle size of the PVA powder is preferably such that it can pass through a sieve with a nominal mesh size (JIS Z 8801-1:2019) of 1.00 mm (16 mesh), and more preferably such that it can pass through a sieve with a nominal mesh size of 500 μm (32 mesh). When the particle size of the PVA powder is such that it can pass through a sieve with a nominal mesh size of 500 μm (32 mesh), drilling slurry containing PVA powder of this particle size can more effectively suppress dewatering from the drilling slurry at high temperatures. As for the lower limit of the particle size of the PVA powder, there is no particular limit as long as the solubility does not become extremely large, but it is preferably such that it cannot pass through a sieve with a nominal mesh size of 45 μm (325 mesh), and more preferably such that it cannot pass through a sieve with a nominal mesh size of 53 μm (280 mesh).

[0103] The PVA powder content in the drilling slurry was 0.5 kg / m³. 3 More than 40kg / m 3 The following is preferable: 3 kg / m 3 More than 30kg / m 3 The following are preferable.

[0104] <muddy> Examples of muddy materials include bentonite, attapulgite, serinite, and hydrated magnesium silicate, with bentonite being the preferred choice.

[0105] The preferred ratio of mud to drilling slurry is 5g to 300g of mud per 1kg of water used in the drilling slurry, and more preferably 10g to 200g.

[0106] <Optional ingredients> As optional components, known additives can be used, such as aqueous solutions of copolymers or derivatives thereof of α-olefins having 2 to 12 carbon atoms and maleic anhydride (e.g., maleic acid amide, maleic acid imide), or their alkali neutralized products; dispersants, pH adjusters, defoamers, thickeners, etc. Examples of copolymers or derivatives thereof of α-olefins having 2 to 12 carbon atoms and maleic anhydride include copolymers or derivatives thereof of α-olefins such as ethylene, propylene, butene-1, isobutene, and diisobutylene (e.g., Kuraray's "Isoban"). Examples of dispersants include humic acid-based dispersants and lignin-based dispersants, among which lignin-based dispersants containing sulfonates are preferred.

[0107] [Cement slurry] The cement slurry of the present invention is used, for example, by injecting and hardening it into the tubular void between the geological formation and the casing pipe installed in the well, to fix the casing pipe in the well and to protect the inner wall of the well. This cement slurry contains a slurry additive, a hardening powder, and a liquid agent. The cement slurry may contain optional components as long as they do not hinder the effects of the present invention.

[0108] Such cement slurry is manufactured by mixing the slurry additive, liquid agent, and hardening powder, along with any optional components as needed, using a stirrer or similar device.

[0109] <Additive for cement slurry> One preferred embodiment is a cement slurry containing a cement slurry additive. The cement slurry additive contains the PVA powder described above. The cement slurry additive may contain only PVA powder. Another preferred embodiment is drilling mud containing PVA(X), a liquid agent, and a hardening powder. Since PVA and PVA powder have been described above, a redundant explanation is omitted here.

[0110] However, in the cement slurry, the particle size of the PVA powder is preferably such that it can pass through a sieve with a nominal mesh size of 1.00 mm (16 mesh), and more preferably such that it can pass through a sieve with a nominal mesh size of 250 μm (60 mesh). When the particle size of the PVA powder is such that it can pass through a sieve with a nominal mesh size of 250 μm (60 mesh), the cement slurry containing PVA powder of this particle size can more effectively suppress dewatering from the cement slurry at high temperatures. As for the lower limit of the particle size of the PVA powder, there is no particular limit as long as the solubility is not excessively high, but it is preferably such that it cannot pass through a sieve with a nominal mesh size of 45 μm (325 mesh), and more preferably such that it cannot pass through a sieve with a nominal mesh size of 53 μm (280 mesh).

[0111] The PVA powder content in the cement slurry is preferably 0.1% (BWOC) or more and 2.0% (BWOC) or less, and more preferably 0.2% (BWOC) or more and 1.0% (BWOC) or less. BWOC (By Weight Of Cement) means based on the mass of cement.

[0112] <Curable powder> Examples of hardening powders include Portland cement, blended cement, eco-cement, and special cement. Hydraulic cement that solidifies upon reaction with water is preferred, and when the cement slurry is used for drilling, geothermal well cement and oil well cement are preferred. One type of hardening powder may be used alone, or two or more types may be used in combination.

[0113] Portland cement can be categorized as specified in JIS R5210:2019. Specifically, Portland cement can be categorized as ordinary Portland cement, rapid-hardening Portland cement, ultra-rapid-hardening Portland cement, moderate-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, and low-alkali Portland cement.

[0114] Examples of blended cements include those specified in JIS R 5211:2019, JIS R 5212:2019, and JIS R 5213:2019, specifically blast furnace cement, silica cement, and fly ash cement.

[0115] Special cements include those based on Portland cement, those with altered components or particle size composition compared to Portland cement, and those with components different from Portland cement.

[0116] Special cements based on Portland cement include expansive cements, two-component low-heat cements, and three-component low-heat cements.

[0117] Special cements that have been modified from Portland cement in terms of composition and particle size include white Portland cement, cement-based solidifying agents (geocement), ultrafine particle cement, and high-belite cement.

[0118] Special cements with different components from Portland cement include ultrafast-setting cement, alumina cement, phosphate cement, and air-setting cement.

[0119] <Liquid formulation> The liquid agent is selected according to the type of curable powder, and examples include water, solvents, and mixtures thereof, but water is generally used. The solvent may be used alone or in combination of two or more types.

[0120] The ratio of hardening powder to liquid in the cement slurry can be appropriately determined according to the specific gravity of the target slurry or the strength of the hardened body. For example, when the cement slurry is constructed as an excavation cement slurry using hydraulic cement, the water-to-cement ratio (W / C) is preferably 25% to 100% by mass, and more preferably 30% to 80% by mass, from the viewpoint of the specific gravity of the slurry and the strength of the hardened body.

[0121] <Optional ingredients> Optional components may include dispersants, retarders, and defoamers, and other additives may also be included. Optional components may be used individually or in combination of two or more.

[0122] (Dispersant) Examples of dispersants include naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, and anionic polymers such as polycarboxylic acid polymers, with naphthalene sulfonic acid formalin condensate being preferred. The dispersant content is usually 0.05% (BWOC) to 2% (BWOC), and preferably 0.2% (BWOC) to 1% (BWOC).

[0123] (Delaying agent) Examples of retarders include oxycarboxylic acids or their salts, monosaccharides, polysaccharides, and other sugars, with sugars being preferred. The retarder content is usually 0.005% (BWOC) to 1% (BWOC), and preferably 0.02% (BWOC) to 0.3% (BWOC).

[0124] (Antifoaming agent) Examples of defoaming agents include alcohol alkylene oxide adducts, fatty acid alkylene oxide adducts, polypropylene glycol, fatty acid soaps, and silicone compounds, with silicone compounds being preferred. The content of the defoaming agent is usually 0.0001% (BWOC) or more and 0.1% (BWOC) or less, and preferably 0.001% (BWOC) or more and 0.05% (BWOC) or less.

[0125] (Additives) The cement slurry may contain additives such as cement quick-setting agents, low-density additives, high-density additives, foaming agents, crack-reducing agents, bubblers, air-entraining agents, cement expansives, cement strength stabilizers, fine aggregates such as silica powder, silica fume, fly ash, limestone powder, crushed sand, coarse aggregates such as crushed stone, and hollow balloons, depending on its intended use and composition. These additives may be used individually or in combination of two or more.

[0126] [Sealing agent for underground treatment] The groundwater treatment sealant of the present invention contains a vinyl alcohol-based polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 90 / 10.

[0127] The ground treatment sealant of the present invention contains the above-mentioned PVA(X). The content of PVA(X) is not particularly limited, but is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass relative to the total ground treatment sealant. The sealant effect tends to be better when the PVA(X) content is within the above range.

[0128] The underground crack sealing agent of the present invention can enter cracks formed during drilling of oil or shale gas, temporarily blocking those cracks and thereby creating new cracks. As a method of blocking cracks using the underground crack sealing agent of the present invention, the underground crack sealing agent may be carried by the fluid flow in the well and flowed into the crack to be blocked.

[0129] Furthermore, the underground sealing agent of the present invention temporarily seals cracks in the ground, but gradually dissolves in water and is removed during or after the recovery of underground resources such as petroleum and natural gas, so it does not remain underground for a long period of time. Therefore, the underground sealing agent of the present invention has an extremely low environmental impact.

[0130] The shape of PVA(X) used as a sealant for underground treatment is not particularly limited and may be in the form of pellets, granules, powder, etc. Conventional methods such as extrusion molding can be used for pelletization, and plasticizers such as polyethylene glycol, as described later, may be added as appropriate.

[0131] When using powdered PVA(X) as a sealant for underground treatment, the average particle size is preferably 10 to 5000 μm, more preferably 50 to 4000 μm, even more preferably 100 to 3500 μm, and particularly preferably 500 to 3000 μm.

[0132] When the average particle size of PVA(X) is within the above range, the PVA-based resin does not scatter and is easier to handle. Furthermore, even when the PVA(X) is later modified, the reaction tends to be more uniform and better. The average particle size is the diameter at which the cumulative value (cumulative distribution) obtained by measuring the volume distribution by particle size using laser diffraction becomes 50%. Specifically, the laser diffraction scattering method can be used, for example, to measure the particle size distribution on a volume basis using a laser diffraction particle size distribution analyzer (SALD-2300: manufactured by Shimadzu Corporation) with a 0.2% sodium hexametaphosphate aqueous solution as the dispersion medium.

[0133] The ground treatment sealant of the present invention may further contain additives. Examples of additives include fillers, plasticizers, and starches. One additive may be used alone, or two or more may be used in combination.

[0134] By mixing the filler with PVA(X), the mechanical properties can be further improved, and the water solubility can be adjusted. The amount of filler added can be appropriately selected depending on the purpose, but for example, it is preferably 50% by mass or less of the total sealant, more preferably 30% by mass or less, and even more preferably 5% by mass or less.

[0135] The specific gravity of the sealant for underground treatment is preferably close to that of the fluid used in the underground treatment, so that it can be distributed more uniformly throughout the system, for example, by pump power. From the viewpoint of adjusting the specific gravity of the sealant for underground treatment, an extender may be added to PVA(X). It is possible to increase the specific gravity of PVA(X) by adding an extender. Examples of extenders include salts of natural minerals, inorganic and organic substances, and may be compounds of one or more metal ions selected from the group consisting of calcium, magnesium, silicon, barium, copper, zinc, and manganese, and one or more counterions selected from the group consisting of fluorides, chlorides, bromides, carbonates, hydroxides, formates, acetates, nitrates, sulfates, and phosphates. Among these, calcium carbonate, calcium chloride, and zinc oxide are preferred.

[0136] To improve the fluid properties of the sealant for underground treatment, the sealant may contain a plasticizer in addition to PVA(X). In other words, PVA(X) may be a mixture with a plasticizer added. In this case, a method of spraying the plasticizer onto the surface of PVA(X) to coat it can be used to homogeneously add the plasticizer to PVA(X). Adding a plasticizer can sometimes further suppress the generation of fine powder. Known plasticizers can be used, and suitable plasticizers include water, glycerol, polyglycerol, ethylene glycol, polyethylene glycol, ethanolacetamide, ethanolformamide, triethanolamine acetate, glycerin, trimethylolpropane, neopentyl glycol, etc. These may be used individually or in combination of two or more. Those that are solid or crystalline at room temperature, such as trimethylolpropane, can be used for spray coating by dissolving them in water or other liquids. The plasticizer content is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on the mass (100% by mass) of PVA(X).

[0137] One preferred embodiment is a ground treatment sealant comprising a composition of PVA(X) and an additive, wherein the additive includes a filler and a plasticizer. In this ground treatment sealant, the preferred proportions of each component are 60-94% by mass of PVA(X), 5-40% by mass of the filler, and 1-15% by mass of the plasticizer.

[0138] Furthermore, in the groundwater treatment sealant of the present invention, starch may be mixed with PVA(X). The amount of starch added is preferably 10 to 90% by mass, and more preferably 30% by mass or more, relative to PVA(X) which is 100% by mass. Examples of starch include natural products, synthetic products, and physically or chemically modified starches.

[0139] The underground sealing agent of the present invention may also contain, as necessary, other additives such as chelating agents, pH adjusters, oxidizing agents, lost circulation materials, scale inhibitors, rust inhibitors, clay, iron agents, reducing agents, and oxygen removers.

[0140] [Multilayer structure] The multilayer structure of the present invention comprises a layer (C) containing a vinyl alcohol-based polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), and a layer (D) containing a resin. The resin is at least one resin selected from the group consisting of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride (PVC) resin, ABS resin, polylactic acid (PLA) resin, polybutylene succinate (PBS) resin, polyhydroxyalkanoate (PHA) resin, polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin, starch, and cellulose.

[0141] [Layer (C)] The layer (C) constituting the multilayer structure of the present invention contains the above-mentioned PVA(X).

[0142] The content of PVA(X) in layer (C) is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 95% by mass or more. Furthermore, in layer (C), the mass ratio of the vinyl alcohol-based polymer to the total polymer components (vinyl alcohol-based polymer / total polymer components) is preferably 0.9 or more, and more preferably the polymer components contained in layer (C) consist substantially only of PVA(X). When it consists substantially only of PVA(X), the content of components other than PVA(X) is preferably less than 0.5% by mass, more preferably less than 0.1% by mass, and even more preferably less than 0.01% by mass.

[0143] [Layer (D)] Layer (D) is a substrate containing a resin. Examples of resins include polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride (PVC) resin, ABS resin, polylactic acid (PLA) resin, polybutylene succinate (PBS) resin, polyhydroxyalkanoate (PHA) resin, polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin, starch, and cellulose. One type of resin may be used alone, or two or more types may be used in combination. The thickness of layer (D) (final thickness if stretched) is preferably 5 to 100 μm.

[0144] Examples of polyolefin resins include polyethylene, polypropylene, copolymerized polypropylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer. Examples of polyethylene include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). Among these, polyethylene and polypropylene are preferred. In this specification, "(meth)acrylic" refers collectively to acrylic and methacrylic. The same applies to expressions such as "(meth)acrylate."

[0145] Examples of polyester resins include polyethylene terephthalate (hereinafter sometimes abbreviated as "PET"), polyethylene naphthalate, polybutylene terephthalate, and polyethylene terephthalate / isophthalate. Among these, polyethylene terephthalate (PET) is preferred.

[0146] Examples of polyamide resins include homopolymers such as polycaproamide (nylon-6), polyundecaneamide (nylon-11), polylauryl lactam (nylon-12), polyhexamethylene adipamide (nylon-6,6), and polyhexamethylene sevacamide (nylon-6,12); caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / aminoundecanoic acid copolymer (nylon-6 / 11), and caprolactam / ω-amide. Examples of copolymers include nononanoic acid polymers (nylon-6,9), caprolactam / hexamethylenediammonium adipate copolymers (nylon-6 / 6,6), caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymers (nylon-6 / 6,6 / 6,12), polymers of adipic acid and metaxylylenediamine, and copolymers of hexamethylenediamine and m,p-phthalic acid, such as aromatic nylons. Among these, polycaproamide (nylon-6) and polyhexamethylene adipamide (nylon-6,6) are preferred.

[0147] As the polyvinyl chloride resin, for example, a homopolymer of vinyl chloride or a copolymer of vinyl chloride and another monomer can be used. Examples of other monomers include α-olefins such as ethylene, propylene, and butylene; dienes such as butadiene and isoprene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl acrylate, phenyl methacrylate, and hydroxyethyl (meth)acrylate; aromatic vinyls such as styrene and α-methylstyrene; vinyl halides such as vinylidene chloride and vinylidene fluoride; N-substituted maleimides such as N-phenyl maleimide and N-cyclohexyl maleimide; (meth)acrylic acid, maleic anhydride, acrylonitrile, and polyorganosiloxane. These may be used individually or in combination of two or more. The monomer copolymerizable with vinyl chloride monomer is preferably in the range of 0 to 50 parts by mass per 100 parts by mass of the total of vinyl chloride and the copolymerizable monomer.

[0148] Examples of ABS (Acrylonitrile Butadiene Styrene) resins include those containing acrylonitrile, butadiene, and styrene as structural units, such as flame-retardant ABS resin, reinforced ABS resin reinforced with glass fibers, and phenylmaleimide-based ABS resin. Furthermore, examples of ABS resins include α-methylstyrene-based ABS resin, in which styrene is replaced with α-methylstyrene; ASA (Acrylonitrile-Styrene-Acrylate resin), in which butadiene is replaced with acrylic rubber; ACS (Chlorinated-polyethylene-Acrylonitrile-Styrene resin), in which butadiene is replaced with chlorinated polyethylene; and AES (Acrylonitrile-Ethylene-Styrene resin), in which butadiene is replaced with EPDM (ethylene propylene diene terpolymer).

[0149] Examples of polylactic acid (PLA) resins include those polymerized with lactic acid monomers as the main component and containing more than 50 mol% of structural units derived from lactic acid. Examples of polylactic acid resins include poly(L-lactic acid), where the structural unit is L-lactic acid; poly(D-lactic acid), where the structural unit is D-lactic acid; poly(DL-lactic acid), where the structural unit is L-lactic acid and D-lactic acid; and polymers mainly composed of mixtures thereof.

[0150] Polybutylene succinate (PBS) resin contains 1,4-butanediol and succinic acid as structural units. In addition to 1,4-butanediol and succinic acid, copolymers obtained by copolymerizing 3-alkoxy-1,2-propanediol can also be used. In the 3-alkoxy-1,2-propanediol used in the copolymer, the alkoxy group preferably has 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. Plant-derived PBS resin may also be used.

[0151] Examples of polyhydroxyalkanoate (PHA) resins include poly(3-hydroxyvaliate), poly(3-hydroxybutyrate), poly(3-hydroxypropionate), poly(4-hydroxybutyrate), poly(3-hydroxyoctanoate), and poly(3-hydroxydecanoate).

[0152] Polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin is a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (3-hydroxybutyrate-co-3-hydroxyhexanoate polymer). In the copolymer, the amount of 3-hydroxyhexanoate may be 1 to 20 mol% in the total structural units.

[0153] Starches include raw starches (automodified starches) such as sorghum starch, potato starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, sorghum starch, rice starch, bean starch, kudzu starch, bracken starch, lotus starch, and water chestnut starch; physically modified starches such as α-starch, fractionated amylose, moist heat-treated starch, and thermochemically modified starch; and hydrolyzed starches. Examples include enzyme-modified starches such as dextrin, enzyme-hydrolyzed dextrin, and amylose; oxidized starches such as acid-treated starch and hypochlorite-oxidized starch; chemically decomposed and modified starches such as dialdehyde starch; chemically modified starch derivatives such as esterified starch, etherified starch, cationized starch, and cross-linked starch; alkyl starch, hydroxyalkyl starch, and hydroxyalkylalkyl starch. Examples of alkyl starch include methyl starch, ethyl starch, and propyl starch. Examples of hydroxyalkyl starch include hydroxymethyl starch, hydroxyethyl starch, and hydroxypropyl starch. Examples of hydroxyalkylalkyl starch include hydroxymethyl methyl starch, hydroxyethyl methyl starch, and hydroxypropyl methyl starch. Examples of esterified starch derivatives include acetic acid esterified starch, succinate esterified starch, nitrate esterified starch, phosphate esterified starch, urea phosphate esterified starch, xanthogenic acid esterified starch, acetoacetate esterified starch, and carbamate esterified starch. Examples of etherified starch include allyl etherified starch, methyl etherified starch, carboxy etherified starch, carboxymethyl etherified starch, hydroxyethyl etherified starch, and hydroxypropyl etherified starch. Examples of cationized starch include reaction products of starch and 2-diethylaminoethyl chloride, and reaction products of starch and 2,3-epoxypropyltrimethylammonium chloride.Examples of cross-linked starches include formaldehyde-cross-linked starch, ebichlorohydrin-cross-linked starch, phosphate-cross-linked starch, and acrolein-cross-linked starch.

[0154] Examples of cellulose include alkylcellulose, hydroxyalkylcellulose, and cellulose acetate. Examples of alkylcellulose include methylcellulose. The methoxy group content in methylcellulose is preferably 26.0 to 33.0% by mass, and more preferably 27.5 to 31.5% by mass. The methoxy group content in methylcellulose can be measured in accordance with the analytical method for methylcellulose in the 17th edition of the Japanese Pharmacopoeia. Examples of hydroxyalkylcellulose include hydroxypropylcellulose. The hydroxypropoxy group content in hydroxypropylcellulose is preferably 53.4 to 80.5% by mass, and more preferably 60.0 to 70.0% by mass. The hydroxypropoxy group content in hydroxypropylcellulose can be measured in accordance with the analytical method for hydroxypropylcellulose in the 17th edition of the Japanese Pharmacopoeia.

[0155] The oxygen permeability of the multilayer structure of the present invention is preferably 150 cc / m³. 2 • day·atm or less, more preferably 100cc / m 2 It is less than or equal to day·atm. In the present invention, the oxygen permeability of the multilayer structure is determined by the method described in the examples.

[0156] Each layer in the multilayer structure of the present invention may contain an inorganic layered compound for the purpose of improving gas barrier properties, strength, or handling. Examples of inorganic layered compounds include micas, talc, montmorillonite, kaolinite, and vermiculite, which may be naturally occurring or synthesized.

[0157] Each layer in the multilayer structure of the present invention may contain a crosslinking agent for the purpose of improving water resistance. Examples of crosslinking agents include epoxy compounds, isocyanate compounds, aldehyde compounds, titanium compounds, silica compounds, aluminum compounds, zirconium compounds, and boron compounds. Among these, silica compounds such as colloidal silica and alkyl silicates are preferred.

[0158] The method for manufacturing the multilayer structure of the present invention is not particularly limited, but a preferred method includes the steps of preparing an aqueous solution containing the vinyl alcohol polymer (X) (hereinafter sometimes abbreviated as PVA(X) aqueous solution) to obtain a coating agent, and coating the coating agent onto the surface of a substrate containing at least one resin selected from the group consisting of polyolefin resin, polyester resin, and polyamide resin. As described later, in a preferred embodiment of the present invention, if a layer such as an adhesive component layer exists between layer (C) and layer (D), the multilayer structure can be manufactured by coating the coating agent onto the layer such as the adhesive component layer formed on the substrate, and in this disclosure, even in such a case, it may be expressed as "coating the coating agent onto the surface of the substrate."

[0159] Examples of the substrate include films made of the resin. In one preferred embodiment, examples of the substrate include films made of polyolefin resin (hereinafter also referred to as polyolefin films), films made of polyester resin (hereinafter also referred to as polyester films), and films made of polyamide resin (hereinafter also referred to as polyamide films). In other preferred embodiments, the substrate may be a film made of polyvinyl chloride (PVC) resin (hereinafter also referred to as a polyvinyl chloride film), a film made of ABS resin (hereinafter also referred to as an ABS film), a film made of polylactic acid (PLA) resin (hereinafter also referred to as a polylactic acid film), a film made of polybutylene succinate (PBS) resin (hereinafter also referred to as a polybutylene succinate film), a film made of polyhydroxyalkanoate (PHA) resin (hereinafter also referred to as a polyhydroxyalkanoate film), a film made of polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin (hereinafter also referred to as a polyhydroxybutyrate / hydroxyhexanoate film), a film made of starch (hereinafter also referred to as a starch film), or a film made of cellulose (hereinafter also referred to as a cellulose film). The substrate will form layer (D).

[0160] The content of PVA(X) in the PVA(X) aqueous solution is not particularly limited, but 5 to 50% by mass is preferred. Within this range, the drying load is reduced and the viscosity of the aqueous solution is appropriate, resulting in better coating properties. A layer (C) is formed by applying the coating agent containing the PVA(X) aqueous solution to the substrate surface and then drying it. The evaporation rate during the drying process is preferably 2 to 2000 g / m². 2 • min, more preferably 50-500 g / m 2 It is the minimum.

[0161] The PVA(X) aqueous solution and coating agent may contain surfactants, leveling agents, etc. Furthermore, from the viewpoint of coatability, the PVA(X) aqueous solution and coating agent may contain lower aliphatic alcohols such as methanol, ethanol, and isopropanol. In this case, the amount of lower aliphatic alcohol contained in the PVA(X) aqueous solution is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of water. From the viewpoint of the working environment, it is preferable that the liquid medium contained in the PVA(X) aqueous solution is water only. Furthermore, the PVA(X) aqueous solution may contain antifungal agents, preservatives, etc. The coating temperature of the PVA(X) aqueous solution is preferably 20 to 80°C. Suitable coating methods include gravure roll coating, reverse gravure coating, reverse roll coating, and wire bar coating. The substrate before coating, or the resulting multilayer structure, may be subjected to stretching or heat treatment. In that case, considering workability, it is preferable to stretch the substrate once, apply a coating agent to the substrate, then stretch it a second time, and perform heat treatment during or after the second stretching.

[0162] The heat treatment is carried out in air or the like. The heat treatment temperature can be adjusted according to the type of substrate, and is usually 140°C to 170°C for polyolefin films. For polyester films and polyamide films, the heat treatment temperature is 140°C to 240°C. For polyvinyl chloride films, the heat treatment temperature is 140°C to 200°C. For ABS films, the heat treatment temperature is 140°C to 170°C. For polylactic acid films, the heat treatment temperature is 140°C to 240°C. For polybutylene succinate films, the heat treatment temperature is 140°C to 240°C. For polyhydroxyalkanoate films, the heat treatment temperature is 140°C to 240°C. For polyhydroxybutyrate / hydroxyhexanoate films, the heat treatment temperature is 140°C to 240°C. For starch films, the heat treatment temperature is 140°C to 240°C. In the case of cellulose film, the heat treatment temperature is 140°C to 240°C. When heat treating layer (C), it is usually done simultaneously with the heat treatment of the substrate layer (D).

[0163] The thickness of layer (C) (or the final thickness after stretching, if stretched) is preferably 0.1 to 20 μm, and more preferably 0.1 to 9 μm. Furthermore, the multilayer structure may include two or more layers (C). The PVA(X) contained in the two or more layers (C) may be the same or different. When the multilayer structure includes two or more layers (C), the thickness of the layer (C) refers to the thickness of a single layer (C).

[0164] In the multilayer structure described above, the thickness ratio of layer (C) to layer (D) ((C) / (D)) is preferably 0.9 or less, and more preferably 0.5 or less. When the multilayer structure includes two or more layers (C), the thickness ratio of layer (D) to each layer (C) is expressed.

[0165] An adhesive component layer may be formed between layer (C) and layer (D) for the purpose of improving adhesion. Examples of adhesive components include anchor coating agents. The adhesive component layer can be formed by applying the adhesive component to the surface of the substrate before applying the coating agent.

[0166] In the multilayer structure of the present invention, a heat-seal resin layer may be further formed on the surface of layer (C) that is not in contact with layer (D). The heat-seal resin layer is usually formed by an extrusion lamination method or a dry lamination method. As the heat-seal resin, polyethylene resins such as HDPE, LDPE, and LLDPE, polypropylene resins, ethylene-vinyl acetate copolymers, ethylene-α-olefin random copolymers, ionomer resins, etc. can be used.

[0167] [Packaging materials] A packaging material comprising the multilayer structure of the present invention is also a preferred embodiment of the present invention. This packaging material, by comprising the multilayer structure of the present invention, exhibits excellent oxygen gas barrier properties.

[0168] This packaging material is used for packaging, for example, food; beverages; pharmaceuticals such as pesticides and medicines; medical equipment; industrial materials such as machine parts and precision materials; and clothing. In particular, this packaging material is suitable for applications where oxygen barrier properties are required, and for applications where the inside of the packaging material is replaced with various functional gases.

[0169] Examples of the packaging material include vertically formed, filled, and sealed bags, vacuum packaging bags, spout pouches, laminated tube containers, and container lids.

[0170] [Paper coating agent] The paper coating agent of the present invention contains a vinyl alcohol-based polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 100 / 0.

[0171] The substrate to which the paper coating agent of the present invention is applied is not particularly limited, but examples include paper, resin-containing substrates, etc. The paper coating agent of the present invention may be used as is, or other components may be added to it.

[0172] Other components mentioned above include those previously stated as components other than vinyl alcohol polymer (X) and water. Other components mentioned above include water-resistant agents such as glyoxal, urea resin, melamine resin, polyvalent metal salts, and water-soluble polyamide resins; pH adjusters such as ammonia, caustic soda, sodium carbonate, and phosphoric acid; release agents; colorants such as pigments; various modified PVAs that do not fall under vinyl alcohol polymer (X), such as unmodified PVA, carboxyl-modified PVA, sulfonic acid group-modified PVA, acrylamide-modified PVA, cationic group-modified PVA, and long-chain alkyl group-modified PVA; casein, raw starch (wheat, corn, rice, potato, sweet potato, tapioca, sago palm), raw starch decomposition products (dextrin, etc.), and lees. Other examples include water-soluble polymers such as powder derivatives (oxidized starch, etherified starch, esterified starch, cationized starch, etc.), seaweed polysaccharides (sodium alginate, carrageenan, agar (agarose, agaropectin), farceran, etc.), and water-soluble cellulose derivatives (carboxyalkylcellulose, alkylcellulose, hydroxyalkylcellulose, etc.); synthetic resin emulsions such as styrene-butadiene copolymer latex, polyacrylic acid ester emulsion, vinyl acetate-ethylene copolymer emulsion, and vinyl acetate-acrylic acid ester copolymer emulsion; and so on. The concentration of the vinyl alcohol-based polymer (X) in the paper coating agent can be arbitrarily selected depending on the coating amount (increase in the dry mass of the paper due to coating), the equipment used for coating, and the operating conditions, but is preferably 1.0 to 30% by mass, and more preferably 2.0 to 25.0% by mass.

[0173] Methods for applying the paper coating agent according to the present invention to paper include known methods, such as coating one or both sides of the paper using equipment such as a size press, gate roll coater, shim sizer, bar coater, or curtain coater, or impregnating the paper with a paper coating liquid (paper coating agent). The coated paper can be dried by known methods, such as hot air, infrared rays, a heating cylinder, or a combination thereof. The barrier properties of the dried coated paper can be further improved by humidity control and calendering. Preferred calendering conditions are a roll temperature of room temperature to 100°C and a roll linear pressure of 20 to 300 kg / cm.

[0174] Another embodiment is coated paper, which is obtained by coating paper with the paper coating agent according to the present invention. Coated paper using the paper coating agent according to the present invention can be used as release paper, oil-resistant paper, gas barrier paper, thermal paper, inkjet paper, pressure-sensitive paper, etc. Among these, release paper or oil-resistant paper is preferred. That is, one embodiment is the above-mentioned coated paper which is release paper or oil-resistant paper.

[0175] The release paper base has a sealing layer (barrier layer) formed by a paper coating liquid on a base material (paper). Examples of base materials (paper) include cardboard such as Manila cardboard, white cardboard, and linerboard; and printing papers such as general fine paper, medium-fine paper, and gravure paper. The release paper has a release layer laminated on top of the sealing layer of the release paper base. The release layer is preferably made of a silicone resin. Examples of silicone resins include known silicone resins, such as solvent-type silicones, solvent-free silicones, and emulsion-type silicones. The amount of coating on the release paper base (increase in the dry mass of the paper due to coating) is not particularly limited, but for example, 0.1 to 5.0 g / m² is preferred. 2 The amount is preferably 0.1 to 2.5 g / m². 2 That is the case.

[0176] Oil-resistant paper has an oil-resistant layer formed on a base material (paper) using a paper coating solution. Examples of base materials (paper) include cardboard such as Manila cardboard, white cardboard, and linerboard; printing paper such as general fine paper, medium-fine paper, and gravure paper; and kraft paper, glassine paper, and parchment paper. The amount of coating (the increase in the dry mass of the paper due to coating) in oil-resistant paper is not particularly limited, but for example, 0.1 to 20 g / m² is a reasonable amount. 2 That is the case.

[0177] The paper coating agent (paper coating liquid) according to the present invention may contain other components besides PVA(X) and water, as long as they do not impair the effects of the present invention. Examples of these other components include resins other than PVA(X), organic solvents, plasticizers, crosslinking agents, surfactants, anti-sedimentation agents, thickeners, flow improvers, preservatives, adhesion improvers, antioxidants, penetrating agents, defoaming agents, fillers, wetting agents, colorants, binders, water-retaining agents, fillers, sugars such as starch and its derivatives, and additives such as latex. These may be used individually or in combination of two or more. The content of these other components in the paper coating agent according to the present invention is preferably 10% by mass or less, and may also be 5% by mass or less, 2% by mass or less, 1% by mass or less, or 0.5% by mass or less.

[0178] [Seed coating composition] The seed coating composition of the present invention contains a vinyl alcohol-based polymer (X) (hereinafter sometimes abbreviated as PVA(X)) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 100 / 0.

[0179] (Pesticides) The seed coating composition may further contain one or more hydrophobic pesticides. In the present invention, "pesticide" is used broadly to refer to agents such as insecticides, fungicides, nematode agents, and similar materials that prevent or reduce damage to seeds from living organisms.

[0180] In the context of the present invention, a "hydrophobic" pesticide additive is one that is either insoluble in water (for example, without the use of a surfactant) or stably dispersible in water.

[0181] Such hydrophobic pesticides are generally well known to those skilled in the art and are commercially available. An example of a commercially available hydrophobic pesticide is Acceleron, a mixture of fungicide and insecticide. TM Examples include packaging (containing pyraclostrobin, fluxapyroxad, metalaxyl, and imidacloprid).

[0182] Examples of suitable fungicides include pyraclostrobin, fluxapiroxad, ipconazole, trifloxystrobin, metalaxyl (metalaxyl 265 ST), fludioxonil (fludioxonil 4L ST), thiabendazole (thiabendazole 4L ST), triticonazole, tefluthrin, and combinations thereof.

[0183] Examples of suitable insecticides include chlorocyanidin, imidacloprid, SENATOR® 600 ST (Nufarm US), tefluthrin, terbuphos, cypermethrin, thiodicarb, lindan, furathiocarb, acephate, and combinations thereof.

[0184] Hydrophobic pesticides are typically used in small amounts (used to achieve the desired pesticide effect in an "effective amount") according to the dosage recommended by the manufacturer of such pesticides.

[0185] (Water-based coating composition) In one preferred embodiment, the seed coating composition is an aqueous coating composition. The aqueous coating composition contains water as the main carrier medium.

[0186] The lower limit of the PVA(X) content in the coating composition is preferably 0.5% by mass, more preferably 1.0% by mass, and still more preferably 2.0% by mass, based on the total mass of the coating composition. The upper limit of the PVA(X) content in the coating composition is preferably 10% by mass, more preferably 8% by mass, and still more preferably 6% by mass, based on the total mass of the coating composition.

[0187] Depending on the optional components described below, the lower limit of the solid content of the aqueous coating composition according to the present invention is preferably 1% by mass, more preferably 2% by mass, and even more preferably 5% by mass, based on the total mass of the aqueous coating composition. The upper limit of the solid content of the aqueous coating composition according to the present invention is preferably 25% by mass, and more preferably 20% by mass, based on the total mass of the aqueous coating composition.

[0188] The aqueous coating composition can also be provided as a concentrate that can be diluted with water for application to seeds.

[0189] Depending on the PVA(X) and other optional components, the aqueous coating composition may be in the form of a solution, dispersion, emulsion, or suspension, as understood by those skilled in the art. For example, some components may be in a solution, while others may be dispersed, emulsified, and / or suspended. In such cases, it is preferable that the components of the aqueous coating composition are substantially evenly distributed in the aqueous coating composition before application. Therefore, it is preferable that the aqueous coating composition is a stable solution, emulsion, and / or dispersion, or a solution, emulsion, dispersion, and / or suspension in which the components can be easily and evenly distributed by conventional means such as stirring with or without gentle heating.

[0190] (optional ingredient) The seed coating composition according to the present invention may contain other optional components in addition to PVA(X). Examples of other optional components include other polymers besides PVA(X), plasticizers, talc, waxes, pigments, and detackeners. These may be used individually or in combination of two or more. For example, other polymers besides PVA(X) can be blended with PVA(X) to enhance coating properties. Examples of other polymers besides PVA(X) include polyvinylpyrrolidone, starch, and high molecular weight polyethylene glycol. Furthermore, plasticizers, talc, waxes, pigments, and detackeners may be added to the seed coating solution, emulsion, or suspension as needed.

[0191] (Application of aqueous coating compositions) Methods for applying aqueous coating compositions to seeds are well known to those skilled in the art. Conventional methods include, for example, mixing, spraying, or a combination thereof. Various coating machines utilizing various coating techniques such as rotary coating machines, drum coating machines, and fluidized beds are commercially available. Seeds may be coated via batch or continuous coating processes.

[0192] The seeds are preferably coated substantially uniformly with a film of the coating composition.

[0193] (Coated seeds) Seeds treated with the seed coating composition according to the present invention include, for example, wheat, barley, rye, sorghum, apples, peaches, cherries, strawberries, blackberries, sugar beets, beets, lentils, peas, soybeans, mustard, olives, sunflowers, palm oil plants, cocoa beans, kukoomba, melons, flax, hemp, oranges, lemons, grapefruits, mandarins, lettuce, asparagus, cabbage, carrots, onions, tomatoes, bell peppers, avocados, flowers, broad-leaved trees, corn, potatoes, bulbs, rice, tobacco, nuts, coffee, and sugarcane.

[0194] [Water-based emulsion] The aqueous emulsion of the present invention comprises a dispersant and a dispersed phase, wherein the dispersed phase comprises a polymer (Y1) containing ethylenically unsaturated monomer units, and the dispersant comprises a vinyl alcohol-based polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 100 / 0.

[0195] The aqueous emulsion of the present invention is an aqueous emulsion comprising the above-mentioned PVA(X) as a dispersant and a polymer (Y1) containing ethylenically unsaturated monomer units as a dispersed phase. There are no particular restrictions on the ratio of PVA(X) to polymer (Y1) containing ethylenically unsaturated monomer units, but the mass ratio ((X) / (Y1)) on a solid content basis is preferably 2 / 98 to 20 / 80, and more preferably 5 / 95 to 15 / 85. When the mass ratio is within the above range, the viscosity stability of the resulting aqueous emulsion tends to be better, and the water resistance of the resulting film tends to be better.

[0196] There are no particular restrictions on the solid content of the aqueous emulsion of the present invention, but it is preferably 30% by mass or more and 60% by mass or less, and more preferably 35% by mass or more and 55% by mass or less.

[0197] [Ethylene-unsaturated monomer units] Ethylene-unsaturated monomers that serve as materials for polymers (Y1) containing ethylenically unsaturated monomer units include, for example, olefin monomers such as ethylene, propylene, and isobutylene; halogenated olefin monomers such as vinyl chloride, vinyl fluoride, vinylidene chloride, and vinylidene fluoride; vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, and vinyl versatate; (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, and 2-hydroxy(meth)acrylate. Examples include (meth)acrylamide monomers such as droxyethyl; (meth)acrylamide monomers such as dimethylaminoethyl (meth)acrylate and its quaternaries, (meth)acrylamide, N-methylol(meth)acrylamide, N,N-dimethyl(meth)acrylamide, (meth)acrylamide-2-methylpropanesulfonic acid and its sodium salts; styrene monomers such as styrene, α-methylstyrene, p-styrenesulfonic acid and their sodium and potassium salts; diene monomers such as butadiene, isoprene, and chloroprene; and N-vinylpyrrolidone. These can be used individually or in combination of two or more.

[0198] The polymer (Y1) containing ethylenically unsaturated monomer units is preferably a polymer having specific units derived from at least one selected from the group consisting of vinyl ester monomers, (meth)acrylic acid ester monomers, styrene monomers, and diene monomers. The content of the above specific units is preferably 70% by mass or more, more preferably 75% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, relative to the total monomer units of the polymer. If the content of the specific units is less than 70% by mass, the emulsion polymerization stability of the aqueous emulsion tends to be insufficient.

[0199] Furthermore, among the above-mentioned specific units, vinyl ester monomers are particularly preferred, and vinyl acetate is the most preferred. Specifically, it is preferable that the content of vinyl ester monomer units be 70% by mass or more relative to the total monomer units of the polymer, more preferably that the content of monomer units derived from vinyl acetate be 70% by mass or more, and even more preferably that the content of monomer units derived from vinyl acetate be 90% by mass or more.

[0200] [Method for producing aqueous emulsion] One example of a method for producing the aqueous emulsion of the present invention is to emulsion polymerize the ethylenically unsaturated monomer using a polymerization initiator in the presence of PVA(X). The aqueous emulsion obtained in this way does not form aggregates and has excellent water resistance.

[0201] In the emulsion polymerization described above, the dispersion medium is preferably an aqueous medium mainly composed of water. The aqueous medium mainly composed of water may contain a water-soluble organic solvent (alcohols, ketones, etc.) that is soluble in water in any proportion. Here, "aqueous medium mainly composed of water" refers to a dispersion medium containing 50% by mass or more of water. From the viewpoint of cost and environmental impact, the dispersion medium is preferably an aqueous medium containing 90% by mass or more of water, and more preferably water.

[0202] In the above method, when PVA(X) is added to the polymerization system as a dispersion stabilizer for emulsion polymerization, there are no particular restrictions on the method of adding or adding it. Examples include adding the dispersion stabilizer for emulsion polymerization to the polymerization system all at once at the beginning, or adding it continuously during emulsion polymerization. Among these, from the viewpoint of increasing the grafting rate of PVA(X) to ethylenically unsaturated monomers, the method of adding the dispersion stabilizer for emulsion polymerization to the polymerization system all at once at the beginning is preferred. In this case, it is preferable to add PVA(X) to cold water or preheated warm water, and then heat and stir it to 80-90°C to uniformly disperse the PVA(X).

[0203] The content of PVA(X) as a dispersion stabilizer for emulsion polymerization during emulsion polymerization is not particularly limited, but is preferably 0.2 parts by mass or more and 40 parts by mass or less, more preferably 0.3 parts by mass or more and 20 parts by mass or less, and even more preferably 0.5 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of ethylenically unsaturated monomer. If the amount of PVA(X) is less than 0.2 parts by mass, the dispersed particles of the aqueous emulsion tend to aggregate, and the polymerization stability tends to decrease. On the other hand, if the amount of PVA(X) exceeds 40 parts by mass, the viscosity of the polymerization system tends to become too high, which tends to prevent uniform emulsion polymerization from proceeding or to result in insufficient removal of polymerization heat.

[0204] In the emulsion polymerization described above, a water-soluble single initiator or a water-soluble redox initiator commonly used in emulsion polymerization can be used as the polymerization initiator. These initiators may be used individually or in combination of two or more. Among these, redox initiators are preferred.

[0205] Examples of water-soluble solitary initiators include azo initiators, hydrogen peroxide, and peroxides such as persulfates (potassium, sodium, or ammonium salts). Examples of azo initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile).

[0206] As a redox initiator, a combination of an oxidizing agent and a reducing agent can be used. Peroxides are preferred as the oxidizing agent. Examples of reducing agents include metal ions and reducing compounds. Combinations of oxidizing and reducing agents include peroxides and metal ions, peroxides and reducing compounds, and peroxides, metal ions, and reducing compounds. Examples of peroxides include hydrogen peroxide, hydroxyperoxides such as cumene hydroperoxide and t-butyl hydroperoxide, persulfates (potassium, sodium, or ammonium salts), t-butyl peracetate, and peracid esters (t-butyl perbenzoate). Examples of metal ions include Fe. 2+ , Cr2+ , V 2+ Co 2+ Ti 3+ Cu + Examples of metal ions capable of undergoing one-electron transfer include sodium bisulfite, sodium bicarbonate, tartaric acid, fructose, dextrose, sorbose, inositol, rongalit, and ascorbic acid. Among these, a combination of one or more oxidizing agents selected from the group consisting of hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate, and one or more reducing agents selected from the group consisting of sodium bisulfite, sodium bicarbonate, tartaric acid, rongalit, and ascorbic acid is preferred, and a combination of hydrogen peroxide and one or more reducing agents selected from the group consisting of sodium bisulfite, sodium bicarbonate, tartaric acid, rongalit, and ascorbic acid is more preferred.

[0207] Furthermore, during emulsion polymerization, alkali metal compounds, surfactants, buffers, polymerization degree regulators, plasticizers, or film-forming aids may be used as appropriate, provided that the effects of the present invention are not impaired.

[0208] The alkali metal compound is not particularly limited as long as it contains an alkali metal (sodium, potassium, rubidium, cesium), and may be the alkali metal ion itself or a compound containing an alkali metal.

[0209] The alkali metal compound content (in alkali metal equivalent) can be appropriately selected depending on the type of alkali metal compound used, but the alkali metal compound content (in alkali metal equivalent) is preferably 100 to 15,000 ppm, more preferably 120 to 12,000 ppm, and even more preferably 150 to 8,000 ppm, relative to the total mass of the aqueous emulsion (in solid equivalent). If the alkali metal compound content is less than 100 ppm, the emulsion polymerization stability tends to decrease, while if it exceeds 15,000 ppm, the resulting film tends to become discolored. The alkali metal compound content can be measured by an ICP emission spectrometer. In this specification, "ppm" means "mass ppm".

[0210] Examples of alkali metal-containing compounds include weakly basic alkali metal salts (e.g., alkali metal carbonates, alkali metal acetates, alkali metal bicarbonates, alkali metal phosphates, alkali metal sulfates, alkali metal halides, alkali metal nitrates) and strongly basic alkali metal compounds (e.g., alkali metal hydroxides, alkali metal alkoxides). These alkali metal compounds can be used individually or in combination of two or more.

[0211] Examples of weakly basic alkali metal salts include alkali metal carbonates (e.g., sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate), alkali metal bicarbonates (e.g., sodium bicarbonate, potassium bicarbonate, etc.), alkali metal phosphates (e.g., sodium phosphate, potassium phosphate, etc.), alkali metal carboxylates (e.g., sodium acetate, potassium acetate, cesium acetate, etc.), alkali metal sulfates (e.g., sodium sulfate, potassium sulfate, cesium sulfate, etc.), alkali metal halide salts (e.g., cesium chloride, cesium iodide, potassium chloride, sodium chloride, etc.), and alkali metal nitrates (e.g., sodium nitrate, potassium nitrate, cesium nitrate, etc.). Of these, alkali metal carboxylates, alkali metal carbonates, and alkali metal bicarbonates, which can behave as salts of weak acids and strong bases upon dissociation, are preferred, and alkali metal carboxylates are more preferred.

[0212] By using these weakly basic alkali metal salts, the weakly basic alkali metal salts act as pH buffers during emulsion polymerization, thereby allowing the emulsion polymerization to proceed stably.

[0213] As the surfactant, any of nonionic surfactants, anionic surfactants, or cationic surfactants may be used. Examples of nonionic surfactants are not particularly limited, but include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, and the like. Examples of anionic surfactants are not particularly limited, but include alkyl sulfates, alkylaryl sulfates, alkyl sulfonates, sulfates of hydroxyalkanols, sulfosuccinates, sulfates and phosphates of alkyl or alkylaryl polyethoxyalkanols, and the like. Examples of cationic surfactants are not particularly limited, but include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamines, and the like. The amount of surfactant used is preferably 2% by mass or less relative to the total amount of ethylenically unsaturated monomers (e.g., vinyl acetate) from the viewpoint of water resistance, hot water resistance, and boiling resistance.

[0214] Examples of buffering agents include acids such as acetic acid, hydrochloric acid, and sulfuric acid; bases such as ammonia, amines, charged sodium, charged potassium, and calcium hydroxide; or alkali carbonates, phosphates, and acetates. Examples of polymerization degree regulators include mercaptans and alcohols.

[0215] The aqueous emulsion of the present invention may contain the following conventionally known plasticizers or film-forming aids. Examples of plasticizers or film-forming aids include dimethyl phthalate, diethyl phthalate, diamyl phthalate, dibutyl phthalate, tributyl acetyl citrate, diisobutyl adipate, dibutyl sebacate, dimethyl glycol adipate, dimethyl glycol sebacate, diethyl glycol sebacate, dimethyl glycol phthalate, diethyl glycol phthalate, dibutyl glycol phthalate, tricresyl phosphate, dioctyl phthalate, texanol, polyethylene glycol monophenyl ether, polypropylene glycol monophenyl ether, benzyl alcohol, butyl carbitol acetate, butyl carbitol, 3-methyl-3-methoxybutanol, ethylene glycol, acetylene glycol butyl cellosolve, ethylene cellosolve, butyl cellosolve, biphenyl chloride, propylene glycol mono-2-ethylhexanoate, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and the like. When adding a plasticizer or film-forming aid, the amount to be added is preferably 1 to 200 parts by mass, and more preferably 2 to 50 parts by mass, per 100 parts by mass of polymer containing an ethylenically unsaturated monomer.

[0216] The aqueous emulsion of the present invention may be modified after emulsion polymerization by adding the following conventionally known fillers, pigments, or other additives. Examples of fillers, fillers, or pigments include calcium carbonate, kaolin clay, pyrophyllite clay, talc, titanium dioxide, iron oxide, pulp, various resin powders, mica, sericite, bentonite, asbestos, calcium silicate, aluminum silicate, diatomaceous earth, silica, anhydrous silicic acid, hydrated silicic acid, magnesium carbonate, aluminum hydroxide, barium sulfate, calcium sulfate, carbon black, and the like. When adding fillers, fillers, or pigments, the amount to be added is preferably 1 to 200 parts by mass, and more preferably 20 to 150 parts by mass, per 100 parts by mass of the polymer (Y1) containing an ethylenically unsaturated monomer.

[0217] The aqueous emulsion of the present invention obtained by the above method can be used for adhesive applications such as woodworking and paper processing, as well as for paints, textile processing, etc., with adhesive applications being particularly preferred. The aqueous emulsion can be used as is, but if necessary, it can be combined with various conventionally known emulsions or commonly used additives to form an emulsion composition, as long as the effects of the present invention are not impaired. Examples of additives include organic solvents (aromatic compounds such as toluene and xylene, alcohols, ketones, esters, halogenated solvents, etc.), crosslinking agents, surfactants, plasticizers, anti-sedimentation agents, thickeners, flow improvers, preservatives, defoamers, fillers, wetting agents, colorants, binders, and water-retaining agents. These may be used individually or in combination of two or more. Examples of crosslinking agents include polyvalent isocyanate compounds, hydrazine compounds, polyamide polyamine epichlorohydrin resins (PAEs), water-soluble aluminum salts such as aluminum chloride and aluminum nitrate, and glyoxal resins such as urea-glyoxal resins. Polyvalent isocyanate compounds are compounds having two or more isocyanate groups in their molecule. Examples of polyvalent isocyanate compounds include tolylene diisocyanate (TDI), hydrogenated TDI, trimethylolpropane-TDI adduct (e.g., Bayer's "Desmodur L"), triphenylmethane triisocyanate, methylene bisphenyl isocyanate (MDI), polymethylene polyphenyl polyisocyanate (PMDI), hydrogenated MDI, polymerized MDI, hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), 4,4-dicyclohexylmethane diisocyanate, and isophorone diisocyanate (IPDI). As polyvalent isocyanate compounds, prepolymers having isocyanate groups at the end groups, which are prepolymerized with an excess of polyisocyanate on a polyol, may also be used. The crosslinking agent may be used alone or in combination of two or more. The crosslinking agent content is preferably 1 to 50 parts by mass per 100 parts by mass of polymer (Y1). When the crosslinking agent content is 1 part by mass or more, the water resistance and heat resistance of the emulsion composition are further improved.On the other hand, if the crosslinking agent content is 50 parts by mass or less, a good film is more easily formed, resulting in superior water resistance and heat resistance.

[0218] The adhesive obtained by the above method can be applied to substrates such as paper, wood, and plastic. Of these materials, the adhesive is particularly suitable for wood and can be applied to laminated wood, plywood, decorative plywood, fiberboard, and other similar applications.

[0219] Furthermore, the aqueous emulsion of the present invention can be used in a wide range of applications, such as inorganic binders, cement admixtures, and mortar primers. Moreover, the obtained aqueous emulsion can also be effectively used as a so-called powdered emulsion, obtained by powdering it through spray drying or other methods.

[0220] [Dispersion stabilizer for suspension polymerization] The present invention provides a dispersion stabilizer for suspension polymerization of vinyl compounds, comprising a vinyl alcohol polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), wherein the molar ratio of (A) / (B) is 5 / 95 to 100 / 0.

[0221] A preferred use of PVA(X) of the present invention is as a dispersion stabilizer for polymerization of vinyl compounds used as monomers (hereinafter also referred to as "vinyl monomers"), and is suitably used in suspension polymerization of vinyl monomers. One preferred embodiment of the present invention is a method for producing a vinyl resin, which includes the step of performing suspension polymerization of a vinyl compound in the presence of the above-mentioned dispersion stabilizer for suspension polymerization.

[0222] Examples of vinyl monomers include vinyl halides such as vinyl chloride; vinyl ester monomers such as vinyl acetate and vinyl propionate; (meth)acrylic acids and their esters and salts; maleic acid, fumaric acid, their esters and anhydrides; styrene, acrylonitrile, vinylidene chloride, vinyl ethers, etc. Of these, suspension polymerization of vinyl chloride alone or together with monomers capable of copolymerizing with vinyl chloride is preferred. Examples of monomers capable of copolymerizing with vinyl chloride include vinyl ester monomers such as vinyl acetate and vinyl propionate; (meth)acrylic acid esters such as methyl (meth)acrylate and ethyl (meth)acrylate; α-olefins such as ethylene and propylene; unsaturated dicarboxylic acids such as maleic anhydride and itaconic acid; acrylonitrile, styrene, vinylidene chloride, vinyl ethers, etc.

[0223] An aqueous medium is preferred as the medium used for the suspension polymerization. Examples of such aqueous mediums include water, or water and an organic solvent. The amount of water in the aqueous medium is preferably 90% by mass or more.

[0224] In the suspension polymerization described above, there are no particular restrictions on the amount of dispersant used, but it is usually 1 part by mass or less per 100 parts by mass of the vinyl compound, and 0.01 to 0.5 parts by mass is preferred.

[0225] When suspend polymerization of vinyl compounds, the preferred mass ratio of aqueous medium to vinyl compound is usually 0.9 to 1.2.

[0226] For the suspension polymerization of vinyl monomers, an oil-soluble or water-soluble polymerization initiator conventionally used for the polymerization of vinyl chloride monomers or the like can be used. Examples of the oil-soluble polymerization initiator include peroxydicarbonate compounds such as diisopropyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, and diethoxyethyl peroxydicarbonate; perester compounds such as t-butyl peroxyneodecanoate, t-butyl peroxypivalate, t-hexyl peroxypivalate, and α-cumyl peroxyneodecanoate; peroxides such as acetyl cyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, 3,5,5-trimethylhexanoyl peroxide, and lauroyl peroxide; and azo compounds such as azobis-2,4-dimethylvaleronitrile and azobis(4-2,4-dimethylvaleronitrile). Examples of the water-soluble polymerization initiator include potassium persulfate, ammonium persulfate, hydrogen peroxide, and cumene hydroperoxide. These oil-soluble or water-soluble polymerization initiators can be used alone or in combination of two or more.

[0227] During the suspension polymerization of vinyl monomers, various other additives can be added to the polymerization reaction system as needed. Examples of the additives include polymerization degree regulators such as aldehydes, halogenated hydrocarbons, and mercaptans, and polymerization inhibitors such as phenolic compounds, sulfur compounds, and N-oxide compounds. In addition, a pH adjuster, a crosslinking agent, etc. can also be added optionally.

[0228] During the suspension polymerization of vinyl monomers, there is no particular limitation on the polymerization temperature, and it can be adjusted to a high temperature exceeding 90°C as well as a low temperature of about 20°C. In addition, in order to enhance the heat removal efficiency of the polymerization reaction system, using a polymerization vessel equipped with a reflux condenser is also one of the preferred embodiments.

[0229] As the dispersion stabilizer, additives such as preservatives, fungicides, anti-blocking agents, defoaming agents, etc. that are usually used in suspension polymerization can be blended as necessary. The content of such additives is usually 1.0% by mass or less. The additives may be used singly or in combination of two or more kinds.

[0230] When the PVA(X) of the present invention is used as a dispersion stabilizer for suspension polymerization, the dispersion stabilizer may be used alone, but it can also be used together with water-soluble cellulose ethers such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose; water-soluble polymers such as polyvinyl alcohol, gelatin; oil-soluble emulsifiers such as sorbitan monolaurate, sorbitan trioleate, glycerin tristearate, ethylene oxide propylene oxide block copolymer; water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, sodium laurate, etc. These may be used singly or in combination of two or more kinds.

[0231] When using PVA(X) of the present invention as a dispersion stabilizer for suspension polymerization, a water-soluble or water-dispersible dispersion stabilizer can be used in combination. As a dispersion stabilizer, a vinyl alcohol polymer (Y2) (hereinafter sometimes abbreviated as PVA(Y2)) can be used. Examples of PVA(Y2) used as a dispersion stabilizer include partially saponified PVA with a degree of saponification of less than 65 mol%. The degree of saponification of partially saponified PVA is preferably 20 mol% or more and less than 60 mol%, more preferably 25 mol% or more and 58 mol%, and even more preferably 30 mol% or more and 56 mol%. Furthermore, the degree of polymerization of other PVA(Y2) is preferably 50 or more and 750 or less, more preferably 100 or more and 700 or less, even more preferably 120 or more and 650 or less, and particularly preferably 150 or more and 600 or less. The method for measuring the degree of saponification and degree of polymerization of PVA(Y2) is the same as for PVA(X). In one preferred embodiment, the dispersion stabilizing agent is a partially saponified PVA (Y2) having a degree of saponification of less than 65 mol% and a degree of polymerization of 50 to 750. In another preferred embodiment, the dispersion stabilizing agent is a partially saponified PVA (Y2) having a degree of saponification of 30 mol% to less than 60 mol% and a degree of polymerization of 180 to 650. The PVA (Y2) used in the dispersion stabilizing agent may be a vinyl alcohol polymer obtained by polymerizing and saponifying a conventional petroleum-derived vinyl ester monomer, or it may be a vinyl alcohol polymer obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B). Furthermore, the dispersion stabilizing agent may be given self-emulsifying properties by introducing ionic groups such as carboxylic acids or sulfonic acids.

[0232] When using a dispersion stabilizer in combination, the mass ratio of the dispersion stabilizer to the dispersion stabilizer (dispersion stabilizer / dispersion stabilizer) varies depending on the type of dispersion stabilizer used, etc., and therefore cannot be uniformly specified. However, a range of 95 / 5 to 20 / 80 is preferred, and 90 / 10 to 30 / 70 is more preferred. The dispersion stabilizer and dispersion stabilizer may be added all at once at the beginning of polymerization, or they may be added in separate batches during polymerization.

[0233] [Dispersion stabilizer for suspension polymerization] The vinyl alcohol polymer (PVA) used in the present invention comprises a vinyl alcohol polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), with a molar ratio of (A) / (B) of 5 / 95 to 100 / 0.

[0234] One preferred use of PVA(X) of the present invention is as a dispersion stabilizing agent for the polymerization of vinyl compounds used as monomers, and is suitably used in the suspension polymerization of vinyl monomers. Examples of vinyl monomers include those similar to those described for the dispersion stabilizer for suspension polymerization.

[0235] An aqueous medium is preferred as the medium used for the suspension polymerization. Examples of such aqueous mediums include water, or water and an organic solvent. The amount of water in the aqueous medium is preferably 90% by mass or more.

[0236] For suspension polymerization of vinyl monomers, oil-soluble or water-soluble polymerization initiators, which have been conventionally used for polymerization of vinyl chloride monomers and the like, can be used. Examples of oil-soluble or water-soluble polymerization initiators are the same as those described for dispersion stabilizers for suspension polymerization.

[0237] During the suspension polymerization of vinyl monomers, various other additives can be added to the polymerization reaction system as needed. Examples of additives include polymerization degree regulators such as aldehydes, halogenated hydrocarbons, and mercaptans, and polymerization inhibitors such as phenol compounds, sulfur compounds, and N-oxide compounds. pH adjusters and crosslinking agents can also be added as desired.

[0238] In the suspension polymerization of vinyl monomers, there are no particular restrictions on the polymerization temperature; it can be adjusted to a low temperature of around 20°C, or to a high temperature exceeding 90°C. Furthermore, in order to improve the heat removal efficiency of the polymerization reaction system, it is also a preferred embodiment to use a polymerizer equipped with a flux condenser.

[0239] Dispersion stabilizers may contain additives such as preservatives, fungicides, blocking inhibitors, and defoamers commonly used in suspension polymerization, as needed. The content of such additives is usually 1.0% by mass or less. Additives may be used individually or in combination of two or more.

[0240] The dispersion stabilizing aid of the present invention can be used in combination with a dispersion stabilizer for suspension polymerization. Another preferred embodiment of the present invention is a method for producing a vinyl resin, which includes a step of performing suspension polymerization of a vinyl compound in the presence of the dispersion stabilizing aid and a dispersion stabilizer for suspension polymerization, wherein the dispersion stabilizer for suspension polymerization contains a vinyl alcohol polymer (Y3) (hereinafter sometimes abbreviated as PVA(Y3)) with a degree of saponification of 65 mol% or more and a viscosity-average degree of polymerization of 600 or more.

[0241] When using PVA(X) of the present invention as a dispersion stabilization aid in suspension polymerization, a dispersion stabilizer containing PVA(Y3) can be used in combination. PVA(Y3) may be a vinyl alcohol polymer obtained by polymerizing and saponifying ordinary petroleum-derived vinyl ester monomers, or it may be a vinyl alcohol polymer (Y3-1) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B).

[0242] The viscosity-average degree of polymerization of PVA(Y3) is preferably 150 to 5,000, more preferably 300 to 4,000, and even more preferably 600 to 3,500. The degree of saponification of PVA(Y3) is preferably 60 mol% to 99.5 mol%, more preferably 65 mol% to 99.2 mol%, and even more preferably 68 mol% to 99.0 mol%. The method for measuring the degree of saponification and polymerization of PVA(Y3) is the same as for PVA(X). PVA(Y3) can be manufactured using conventionally known methods. The method for manufacturing vinyl alcohol polymer (Y3-1) is the same as for PVA(X). The polymerization conditions and saponification conditions can be set appropriately to the desired range described above. In one preferred embodiment, PVA(Y3) has a degree of saponification of 65 mol% or more and a viscosity-average degree of polymerization of 600 or more. In another preferred embodiment, the viscosity-average degree of polymerization is 500 to 5000, and the degree of saponification is 65 mol% to 99 mol%.

[0243] When using a dispersion stabilizer in combination, the mass ratio of the dispersion stabilizer to the dispersion stabilizing aid (dispersion stabilizer / dispersion stabilizing aid) varies depending on the type of dispersion stabilizer used, etc., and therefore cannot be uniformly specified. However, a range of 95 / 5 to 20 / 80 is preferred, and 90 / 10 to 30 / 70 is more preferred. The dispersion stabilizer and dispersion stabilizing aid may be added all at once at the beginning of polymerization, or they may be added in separate batches during polymerization.

[0244] The aforementioned dispersion stabilizing aid for suspension polymerization may be used in combination with water-soluble cellulose ethers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, which are commonly used when suspend polymerization of vinyl compounds in an aqueous medium; water-soluble polymers such as gelatin; oil-soluble emulsifiers such as sorbitan monolaurate, sorbitan triolate, glycerin tristearate, and ethylene oxide propylene oxide block copolymer; and water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, and sodium laurate. There are no particular restrictions on the amount added, but it is preferable to add 0.01 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the vinyl compound.

[0245] There are no particular restrictions on how the above-mentioned dispersion stabilizer for suspension polymerization is added to the polymerization tank during the suspension polymerization of vinyl compounds. An aqueous solution of the dispersion stabilizer for suspension polymerization may be prepared and added. Alternatively, a mixed solution of the dispersion stabilizer for suspension polymerization with water and methanol or ethanol may be prepared and added. Alternatively, an aqueous solution containing the above-mentioned dispersion stabilizer for suspension polymerization and the dispersion stabilizer for suspension polymerization may be mixed and added. Furthermore, the aqueous solution of the dispersion stabilizer for suspension polymerization and the aqueous solution of the dispersion stabilizer for suspension polymerization may be added separately.

[0246] When performing suspension polymerization of vinyl compounds, the amount of the above-mentioned dispersion stabilizing agent for suspension polymerization to be charged into the polymerization tank is not particularly limited, but it is preferable to charge the aqueous solution of the dispersion stabilizing agent for suspension polymerization so that the amount of PVA(X) relative to the vinyl compound (e.g., vinyl chloride monomer) is 30 ppm or more and 1000 ppm or less, more preferably 50 ppm or more and 800 ppm or less, and even more preferably 100 ppm or more and 500 ppm or less.

[0247] By subjecting a vinyl-based compound to suspension polymerization in the presence of the above-described dispersion stabilizer for suspension polymerization by the method as described above, vinyl-based polymer particles can be obtained that have high absorbability of a plasticizer, no foreign matters such as fish eyes, little formation of coarse particles, and are also easy to remove the remaining monomer components. The obtained vinyl-based polymer particles can be blended with a plasticizer or the like as appropriate and used for various molded product applications.

Examples

[0248] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited by these examples. In the examples, "parts" and "%" mean mass basis unless otherwise specified.

[0249] (Content ratio of ethylene unit in ethylene-modified PVA) The content ratio of the ethylene unit in the ethylene-modified PVA is that of the ethylene-modified vinyl ester polymer which is a precursor or reacetylated product of the ethylene-modified PVA 1 was determined from 1H-NMR. Specifically, after the ethylene-modified vinyl ester polymers of the samples of Synthesis Examples 7-3 and 7-5 were reprecipitated and purified three or more times using a mixed solution of n-hexane and acetone, they were dried under reduced pressure at 80 °C for 3 days to prepare an ethylene-modified vinyl ester polymer for analysis. The ethylene-modified vinyl ester polymer for analysis was dissolved in DMSO-d6 and 1 1H-NMR (500 MHz) was measured. Using the peak (integral value P: 4.7 to 5.2 ppm) derived from the main-chain methine proton of vinyl acetate and the peak (integral value Q: 1.0 to 1.6 ppm) derived from the main-chain methylene protons of ethylene and vinyl acetate, the content ratio of the ethylene unit was calculated by the following formula. Content ratio of ethylene unit (mol%) = 100 × ((Q - 2P) / 4) / P

[0250] (Viscosity-average degree of polymerization of PVA) The viscosity-average degree of polymerization of PVA was measured in accordance with JIS K 6726:1994. Specifically, if the degree of saponification was less than 99.5 mol%, the viscosity-average degree of polymerization was calculated using the following formula with the intrinsic viscosity [η] (dL / g) measured in water at 30°C for PVA that had been saponified to a degree of saponification of 99.5 mol% or more, or for ethylene-modified PVA. Viscosity average degree of polymerization = ([η]×1000 / 8.29) (1 / 0.62)

[0251] (Degree of saponification of PVA) The degree of saponification of PVA was measured in accordance with JIS K 6726:1994.

[0252] (Synthesis Example 1-1) A silica spherical support was impregnated with an aqueous solution containing sodium tetrachloropalladate aqueous solution and tetrachloroaurate tetrahydrate aqueous solution, in an amount equivalent to the support's water absorption capacity. It was then immersed in an aqueous solution containing sodium metasilicate nonahydrate and allowed to stand. Subsequently, an aqueous solution of hydrazine hydrate was added, and after standing at room temperature, it was washed with water until no chloride ions remained in the water, and then dried. The palladium / gold / support composition was immersed in an aqueous acetic acid solution and allowed to stand. Next, it was washed with water and dried. Afterward, it was impregnated with an aqueous solution of potassium acetate in an amount equivalent to the support's water absorption capacity, and dried to obtain a vinyl acetate synthesis catalyst.

[0253] The catalyst obtained above was diluted with glass beads and packed into a SUS reaction tube. A mixed gas of ethylene, oxygen, water, acetic acid, and nitrogen was passed through the tube to carry out the reaction. Bioethylene derived from sugarcane (manufactured by Braskem SA) was used. Acetic acid was vaporized and then introduced into the reaction system as steam. The yield and selectivity of vinyl acetate were obtained by analyzing the reaction outlet gas. The obtained vinyl acetate was analyzed using the method described above. 14 When the C / C ratio was measured, it was 5.0 × 10 -13 That was the case.

[0254] (Synthesis Example 1-2) PVA was synthesized using the following method, with a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in the above synthesis example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials.

[0255] Into a 250 L reaction tank equipped with a stirrer, a nitrogen inlet, an ethylene inlet, an initiator addition port, and a delay solution addition port, 127.5 kg of the above vinyl acetate and 22.5 kg of methanol were charged, and the temperature was raised to 60 °C. Then, nitrogen substitution was carried out by nitrogen bubbling for 30 minutes. Next, ethylene was introduced so that the pressure in the reaction tank became 3.4 Kg / cm2. A reaction initiation solution with a concentration of 2.8 g / L of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (AMV) dissolved in methanol was prepared as an initiator. This reaction initiation solution was bubbled with nitrogen gas for nitrogen substitution. 45 mL of this initiator solution was injected into the reaction tank adjusted to 60 °C to start polymerization. During polymerization, ethylene was introduced to maintain the pressure in the reaction tank at 3.4 kg / cm 2 and the polymerization temperature was maintained at 60 °C. The initiator solution was continuously added to the reaction tank at 143 mL / hr to carry out polymerization. When the polymerization rate reached 50% after 5 hours, the reaction tank was cooled to stop polymerization. Further, after opening the reaction tank to remove ethylene, nitrogen gas was bubbled to completely remove ethylene. Next, the unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. Methanol was added to this polyvinyl acetate solution to adjust the concentration of polyvinyl acetate to 25% by mass. Further, 23.3 g (molar ratio of 0.1 with respect to the vinyl acetate units in polyvinyl acetate) of an alkaline solution (10% by mass methanol solution of NaOH) was added to 400 g of this methanol solution of polyvinyl acetate (100 g of polyvinyl acetate in the solution) for saponification. Approximately 1 minute after adding the alkali, the gelled product was pulverized with a pulverizer and left at 40 °C for 1 hour to allow saponification to proceed. Then, 1000 g of methyl acetate was added and left at room temperature for 30 minutes. 1000 g of methanol was added to the white solid (PVA) obtained by filtration and washing was carried out by leaving it at room temperature for 3 hours. After centrifugal dewatering, the obtained PVA was left in a dryer at 100 °C for 3 hours to obtain PVA (PVA1-1).

[0256] <Characterization of PVA> For PVA (PVA1-1), the degree of saponification, the average degree of polymerization, and the ratio of ethylene units were analyzed according to the following methods.

[0257] (Degree of saponification) The degree of saponification of PVA (PVA1-1) was measured in accordance with JIS K 6726:1994 and was found to be 99.5 mol%.

[0258] (Average degree of polymerization) The methanol solution of polyvinyl acetate obtained by removing the unreacted vinyl acetate monomer after polymerization in Synthesis Example 1-2 was saponified with an alkali molar ratio of 0.5, then pulverized and allowed to stand at 60°C for 5 hours to allow saponification to proceed. Subsequently, methanol Soxhlet treatment was performed for 3 days, followed by vacuum drying at 80°C for 3 days to obtain purified PVA. The average degree of polymerization of this purified PVA was measured in accordance with JIS K 6726:1994 and was found to be 2,450.

[0259] (Percentage of ethylene units) The methanol solution of polyvinyl acetate obtained by removing the unreacted vinyl acetate monomer after polymerization in Synthesis Example 1-2 was purified by precipitation in n-hexane and reprecipitation in acetone three times, and then dried under reduced pressure at 80°C for 3 days to obtain purified polyvinyl acetate. This purified polyvinyl acetate was dissolved in DMSO-d6, and the ethylene unit content was measured at 80°C using a 500 MHz proton NMR (JEOL GX-500), which was found to be 3.0 mol%.

[0260] (Synthesis Examples 1-3) Using a uniform mixture of 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate as raw materials, PVA (PVA1-2) was synthesized in the same manner as Synthesis Example 1-2, except that ethylene was not introduced. The degree of saponification of PVA1-2 was 99.5 mol%, the average degree of polymerization was 2,640, and the ethylene units were 0 mol%.

[0261] (Synthesis Examples 1-4) PVA (PVA1-3) was synthesized using conventional petroleum-derived vinyl acetate as the raw material, in the same manner as in Synthesis Example 1-2. The degree of saponification of PVA1-3 was 99.6 mol%, the average degree of polymerization was 2,480, and the ethylene units were 3.0 mol%.

[0262] (Synthesis Examples 1-5) PVA (PVA1-4) was synthesized using conventional petroleum-derived vinyl acetate as the raw material, in the same manner as in Synthesis Example 1-3. The degree of saponification of PVA1-4 was 99.6 mol%, the average degree of polymerization was 2,580, and the ethylene units were 0 mol%.

[0263] [Example 1-1] <Preparation of cement slurry> PVA (PVA1-1) was sieved through a sieve with a nominal mesh size of 250 μm (60 mesh). 4 g of the PVA powder that passed through this sieve was added to a juice mixer along with 320 g of deionized water, 800 g of well-grade Class H cement, 4 g of naphthalene sulfonate formalin condensate sodium salt (Dipersity Technologies' "Daxad-19"), and 0.16 g of lignin sulfonate sodium salt (Lignotech USA's "Keling 32L"), and stirred to prepare cement slurry (S-1). The amount of PVA powder added was 0.5% by mass (BWOC) of the cement. As described above, the PVA powder had a particle size distribution (by volume) of less than 250 μm, as determined by the sieving method.

[0264] [Examples 1-2] A cement slurry (S-2) was prepared in the same manner as in Example 1-1, except that PVA (PVA1-2) was used.

[0265] [Reference example 1-1] A cement slurry (s-1) was prepared in the same manner as in Example 1-1, except that PVA (PVA1-3) was used.

[0266] [Reference example 1-2] A cement slurry (s-2) was prepared in the same manner as in Example 1-2, except that PVA (PVA1-4) was used.

[0267] [evaluation] The viscosity and dewatering rate of the cement slurries (S-1), (S-2), and (s-1), (s-2) of Examples 1-1, 1-2 and Reference Examples 1-1, 1-2 were evaluated according to the method described below. The evaluation results are shown in Table 1. In addition, the solubility of the PVA used in the preparation of these cement slurries in water is also shown in Table 1.

[0268] <Solubility in water> 4 g of PVA powder was added to a 300 mL beaker containing 100 g of water at 60°C. The mixture was stirred for 3 hours at 280 rpm under 60°C conditions using a magnetic stirrer equipped with a 3 cm long bar, while preventing the water from evaporating. The undissolved powder was then separated using a wire mesh with a nominal mesh size of 75 μm (200 mesh). The undissolved PVA powder was dried in a 105°C oven for 3 hours, and its mass was measured. The solubility of the PVA powder was calculated from the mass of the undissolved PVA powder and the mass of the PVA powder added to the beaker (4 g).

[0269] <Viscosity> Viscosity was evaluated as plastic viscosity (PV) and yield value (YV). Plastic viscosity (PV) is the flow resistance value caused by the mechanical friction of the solids contained in the cement slurry. Yield value (YV) is the shear force required for a fluid to continue flowing when it is in a flowing state, and is the flow resistance caused by the tensile force between the solid particles contained in the cement slurry.

[0270] Plastic viscosity (PV) and yield value (YV) were measured by adjusting the cement slurry temperature to 25°C or 90°C and following the method described in "Appendix H" of "API10" (American Institute Specification 10). The plastic viscosity (PV) and yield value (YV) were calculated using the following formulas. Plastic viscosity (PV) = (reading at 300 rpm - reading at 100 rpm) × 1.5 Yield value (YV) = (reading at 300 rpm - plastic viscosity)

[0271] <Dehydration amount> The amount of water removed was measured as the amount of water removed from a cement slurry heated to 90°C in 30 minutes under a differential pressure of 1000 psi, according to the method described in "Appendix H" of "API10" (American Institute Specification 10). [Table 1]

[0272] As is clear from the results in Table 1, the cement slurries (S-1) and (S-2) of Examples 1-1 and 1-2 exhibited excellent viscosity, with dewatering amounts of 25 mL and 32 mL, respectively, at 150°C, indicating suppressed dewatering at high temperatures. These values ​​were comparable to those of the cement slurries (S-1) and (S-2) of Reference Examples 1-1 and 1-2, which were PVA synthesized solely from petroleum-derived vinyl acetate, demonstrating equivalent performance as cement slurries. Furthermore, it was visually confirmed that the cement slurries (S-1) and (S-2) of Examples 1-1 and 1-2 did not separate. Such cement slurries can contribute to the conservation of petroleum resources and the mitigation of global warming.

[0273] <Drilling slurry> (Synthesis Examples 1-6) Preparation of PVA (PVA1-5) PVA was synthesized using the following method, with a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in the above synthesis example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials.

[0274] In a 250 L reaction vessel equipped with a stirrer, nitrogen inlet, ethylene inlet, initiator addition port, and delay solution addition port, 127.5 kg of vinyl acetate and 22.5 kg of methanol were charged and the temperature was raised to 60°C, after which the vessel was purged with nitrogen by nitrogen bubbling for 30 minutes. Subsequently, the pressure in the reaction vessel was reduced to 4.9 kg / cm². 2Ethylene was introduced so as to achieve [the desired state]. A reaction initiation solution with a concentration of 2.8 g / L in which 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (AMV) was dissolved in methanol was prepared as an initiator. This reaction initiation solution was subjected to bubbling with nitrogen gas for nitrogen substitution. 45 mL of this initiator solution was injected into a reaction vessel adjusted to 60 °C to initiate polymerization. During polymerization, ethylene was introduced to maintain the pressure in the reaction vessel at 4.9 Kg / cm 2 and the polymerization temperature was maintained at 60 °C. The initiator solution was continuously added to the reaction vessel at 143 mL / hr to carry out polymerization. When the polymerization rate reached 40% after 4 hours, the reaction vessel was cooled to stop the polymerization. Further, after opening the reaction vessel to remove ethylene and then performing bubbling with nitrogen gas to completely remove ethylene, unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. Methanol was added to this polyvinyl acetate solution to adjust the concentration of polyvinyl acetate to 25 mass%. Further, 23.3 g (molar ratio of 0.1 with respect to vinyl acetate units in polyvinyl acetate) of an alkaline solution (10 mass% methanol solution of NaOH) was added to 400 g of this methanol solution of polyvinyl acetate (100 g of polyvinyl acetate in the solution) for saponification. Approximately 1 minute after adding the alkali, the gelled product was pulverized with a pulverizer and left at 40 °C for 1 hour to allow saponification to proceed. Then, 1000 g of methyl acetate was added and left at room temperature for 30 minutes. 1000 g of methanol was added to the white solid (PVA) obtained by filtration and washing was carried out by leaving at room temperature for 3 hours. After centrifugal draining, the obtained PVA was left in a dryer at 100 °C for 3 hours to obtain PVA (PVA1-5).

[0275] <Characterization of PVA> Regarding PVA (PVA1-5), the degree of saponification, average degree of polymerization, and proportion of ethylene units were analyzed according to the following methods.

[0276] (Degree of saponification) When the degree of saponification of PVA (PVA1-5) was measured according to JIS K6726:1994, it was 99.9 mol%.

[0277] (Average degree of polymerization) The methanol solution of polyvinyl acetate obtained by removing the unreacted vinyl acetate monomer after polymerization in Synthesis Examples 1-6 was saponified with an alkali molar ratio of 0.5, then pulverized and allowed to stand at 60°C for 5 hours to allow saponification to proceed. Subsequently, methanol Soxhlet treatment was performed for 3 days, followed by vacuum drying at 80°C for 3 days to obtain purified PVA. The average degree of polymerization of this purified PVA was measured according to JIS K6726:1994 and was found to be 1,720.

[0278] (Ethylene content) The methanol solution of polyvinyl acetate obtained by removing the unreacted vinyl acetate monomer after polymerization in Synthesis Examples 1-6 was purified by precipitation in n-hexane and reprecipitation by dissolving in acetone three times, and then dried under reduced pressure at 80°C for 3 days to obtain purified polyvinyl acetate. This purified polyvinyl acetate was dissolved in DMSO-d6 and heated at 500 MHz. 1 The percentage of ethylene units was measured at 80°C using 1H-NMR (JEOL GX-500) and was found to be 5.0 mol%.

[0279] (Synthesis Examples 1-7) Preparation of PVA (PVA1-6) Using a uniform mixture of 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate as raw materials, PVA (PVA1-6) was synthesized in the same manner as Synthesis Example 1-6, except that ethylene was not introduced. The degree of saponification of PVA1-6 was 99.9 mol%, the average degree of polymerization was 2,520, and the ethylene units were 0 mol%.

[0280] (Synthesis Examples 1-8) PVA (PVA1-7) was synthesized using conventional petroleum-derived vinyl acetate as the raw material, in the same manner as in Synthesis Example 1-6. The degree of saponification of PVA1-7 was 99.9 mol%, the average degree of polymerization was 1,740, and the ethylene units were 5.0 mol%.

[0281] (Synthesis Examples 1-9) PVA (PVA1-8) was synthesized using conventional petroleum-derived vinyl acetate as the raw material, in the same manner as in Synthesis Example 1-7. The degree of saponification of PVA1-8 was 99.9 mol%, the average degree of polymerization was 2,480, and the ethylene units were 0 mol%.

[0282] [Examples 1-3] <Preparation of drilling slurry> 300g of deionized water was placed in a Hamilton Beach mixer cup, 6g of bentonite (Ternite's "Tergel E") was added and thoroughly mixed, and then left for 24 hours to allow the bentonite to swell sufficiently. Meanwhile, PVA (PVA1-5) was sieved through a sieve with a nominal mesh size of 1.00 mm (16 mesh), and 1.5g of the PVA (PVA1-5) powder that passed through the sieve was collected. This powder was added to the bentonite dispersion to obtain drilling slurry (D-1). As described above, the PVA powder had a particle size distribution (by volume) of less than 1.00 mm in the sieving method.

[0283] [Examples 1-4] Drilling slurry (D-2) was prepared in the same manner as in Examples 1-3, except that PVA (PVA1-6) powder was used.

[0284] [Reference example 1-3] Drilling slurry (d-1) was prepared in the same manner as in Examples 1-3, except that PVA (PVA1-7) powder was used.

[0285] [Reference example 1-4] Drilling slurry (d-2) was prepared in the same manner as in Examples 1-3, except that PVA (PVA1-8) powder was used.

[0286] [evaluation] The viscosity and dewatering rate of drilling slurry (D-1), (D-2), and (d-1), (d-2) were evaluated according to the method described below. In addition, the solubility in water of PVA (PVA1-5) to (PVA1-8) used in the preparation of these drilling slurry solutions was evaluated according to the method described below. The evaluation results are shown in Table 2.

[0287] <Solubility in water> 4 g of PVA powder was added to a 300 mL beaker containing 100 g of water at 60°C. The mixture was stirred for 3 hours at 280 rpm under 60°C conditions using a magnetic stirrer equipped with a 3 cm long bar, while preventing the water from evaporating. The undissolved powder was then separated using a wire mesh with a nominal mesh size of 75 μm (200 mesh). The undissolved PVA powder was dried in a 105°C oven for 3 hours, and its mass was measured. The solubility of the PVA powder was calculated from the mass of the undissolved PVA powder and the mass of the PVA powder added to the beaker (4 g).

[0288] <Viscosity> The viscosity of the drilling slurry was measured using a Type B viscometer at 25°C and 30 rpm, and the value after 10 seconds was used.

[0289] <Dehydration amount> The amount of drilling slurry dewatered was measured using Fann Instrument's "HPHT Filter Press Series 387." Drilling slurry was poured into a cell adjusted to a temperature of 150°C and left for 3 hours. Then, pressure was applied from the top and bottom of the cell to achieve a differential pressure of 500 psi.

[0290] [Table 2]

[0291] As is clear from the results in Table 2, the drilling slurry (D-1) and (D-2) of Examples 1-3 and 1-4 had low viscosity and a dewatering amount of 25 mL or less at 150°C, indicating that dewatering at high temperatures was kept to a minimum. Furthermore, these values ​​were comparable to the drilling slurry (d-1) and (d-2) of Reference Examples 1-3 and 1-4, which were PVA synthesized solely from petroleum-derived vinyl acetate, demonstrating equivalent performance as drilling slurry. Such drilling slurry can contribute to the conservation of petroleum resources and the mitigation of global warming.

[0292] (Synthesis Example 2-2) Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method by copolymerizing methyl acrylate at a concentration of 5 mol%. This was then used as a methanol solution, and saponification was carried out with an alkaline catalyst, followed by drying to obtain PVA. The average degree of polymerization of this PVA was 1,450, and the degree of saponification was 99.5 mol%. 1.5 mass% polyethylene glycol was added to the obtained PVA and kneaded. Next, it was extruded into a sheet using a twin-screw extruder at a molding pressure of 1259 psi. This was then fed into a granulator and granulated to a 6 / 8 mesh (ASTM E11 standard) to obtain PVA resin pellets (PVA2-1). "Granulation to a 6 / 8 mesh" means granulating to a particle size that passes through a 6-mesh mesh but not an 8-mesh mesh, and the particle diameter of particles granulated to a 6 / 8 mesh is between 2380 μm and 3350 μm.

[0293] (Synthesis Example 2-3) Using a uniform mixture of 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate as raw materials, PVA was obtained in the same manner as in Synthesis Example 2-2, except that methyl acrylate was not copolymerized. The average degree of polymerization of this PVA was 1,620 and the degree of saponification was 99.5 mol%. 1.5% by mass of polyethylene glycol was added to the obtained PVA and kneaded. Then, using a twin-screw extruder, it was extruded into a sheet at a molding pressure of 1250 psi. This was then fed into a granulator and granulated to a 6 / 8 mesh to obtain PVA resin pellets (PVA2-2).

[0294] (Synthesis Example 2-4) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin pellets (PVA2-3) were synthesized in the same manner as in Synthesis Example 2-2. The degree of saponification of this PVA was 99.5 mol%, the average degree of polymerization was 1,480, and the methyl acrylate content was 5 mol%.

[0295] (Synthesis Example 2-5) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin pellets (PVA2-4) were synthesized in the same manner as in Synthesis Example 2-3. The degree of saponification of this PVA was 99.6 mol%, and the average degree of polymerization was 1,580.

[0296] [Examples 2-1 and 2-2, Reference Examples 2-1 and 2-2] <Sealing agent for underground treatment> The degree of swelling (%) with water and solubility (%) in water were measured for the obtained PVA2-1 to PVA2-4 using the method described below, and the sealing effect was evaluated. The results are shown in Table 3.

[0297] <Degree of swelling due to water> 0.5 g of PVA resin pellets were placed in a test tube with an inner diameter of 18 mm, and the height occupied by the PVA resin pellets in the test tube was measured (height A). Next, 7 mL of distilled water was added to the test tube and shaken well to disperse the PVA resin pellets. Then, the test tube was immersed in a water bath set to 40°C, and after the water temperature in the test tube reached 40°C, it was left to stand for 30 minutes, and the height occupied by the PVA resin pellets in the test tube was measured again (height B). From the obtained values ​​of height A and height B, the degree of swelling by water (%) was calculated according to the following formula. Swelling degree due to water (%) = (height B / height A) × 100

[0298] <Solubility in water> 100 g of distilled water was placed in a 200 mL glass container with a lid, and 6 g of PVA resin pellets were added. The mixture was left to stand in a 65°C constant temperature bath for 5 hours. After that, the contents of the glass container were passed through a 120 mesh nylon sieve (125 micron mesh opening), and the PVA resin pellets remaining on the sieve were dried at 140°C for 3 hours. The mass after drying was measured (mass A). Separately from the above PVA resin pellets, PVA resin pellets were collected from the same sample for solid content measurement. These pellets were dried at 105°C for 3 hours, and the mass before drying (mass B) and the mass after drying (mass C) were measured to calculate the solid content. Using the solid content and mass A, the solubility (%) of the PVA resin pellets in water was calculated according to the following formula. Solid content percentage (%) = (mass C / mass B) × 100 Solubility in water (%) = {6 - (mass A × 100 / solid content)} / 6 × 100

[0299] <Sealing effect confirmation test> A 120-mesh stainless steel sieve was placed inside a 10mm inner diameter stainless steel column, and 5g of PVA resin pellets were placed on the upstream side. Next, hot water adjusted to 50°C was introduced into the column, and a pressure of 100 psi was applied. The column was visually observed, and the sealing effect was evaluated by marking "○" if the outflow of hot water stopped within 15 seconds, and "×" if it did not stop within 15 seconds.

[0300] [Table 3]

[0301] The PVA resin pellets of Examples 2-1 and 2-2 exhibited comparable solubility and swelling properties to those of Reference Examples 2-1 and 2-2, respectively, confirming similar levels of (thermal) water solubility and swelling. Furthermore, they effectively seal cracks and contribute to the conservation of petroleum resources and the mitigation of global warming. Such PVA-containing ground treatment sealants gradually dissolve in water while temporarily sealing cracks in the ground, and are removed during or after the recovery of underground resources such as petroleum and natural gas. As a result, they do not remain underground for extended periods, thus reducing the environmental burden.

[0302] (Synthesis Example 2-6) Using 100 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 above, and without adding any ordinary petroleum-derived vinyl acetate, PVA was obtained in the same manner as in Synthesis Example 2-3. The average degree of polymerization of this PVA was 1,580, and the degree of saponification was 99.6 mol%. 1.5% by mass of polyethylene glycol was added to the obtained PVA and kneaded. Then, using a twin-screw extruder, it was extruded into a sheet at a molding pressure of 1250 psi. This was then fed into a granulator and granulated to a 6 / 8 mesh to obtain PVA resin pellets (PVA2-5).

[0303] [Comparative Example 2-1] The obtained PVA2-5 exhibited cracking, in contrast to the smooth appearance of PVA2-3, obtained using a similar method. While the reason for this is not entirely clear, it has been confirmed that increasing the plant-derived vinyl acetate content in the raw materials to 10 mol% or more can improve the cracking of the PVA.

[0304] In this invention, a vinyl alcohol polymer with properties equivalent to those of a vinyl alcohol polymer derived solely from petroleum was obtained by using a plant-derived vinyl ester monomer (A) as the monomer. It was confirmed that the occurrence of manufacturing problems that occur when PVA is produced can be suppressed. Furthermore, when using PVA, petroleum resources can be conserved and carbon dioxide emissions during the manufacturing process can be suppressed.

[0305] (Synthesis Example 3-2) Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method by adjusting polymerization conditions such as polymerization temperature and polymerization time to the desired range. This was then used as a methanol solution, and the saponification conditions such as the amount of alkaline catalyst used and saponification time were adjusted to the desired range. The reaction was carried out with an alkaline catalyst according to a conventional method, and the mixture was dried to obtain PVA (PVA3-1). The average degree of polymerization of this PVA was 1,750, and the degree of saponification was 88.5 mol%.

[0306] (Synthesis Example 3-3) PVA (PVA3-2) was obtained by the same method as in Synthesis Example 3-2, except that 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate were uniformly mixed as raw materials and copolymerized with ordinary petroleum-derived ethylene. The average degree of polymerization of this PVA was 1,720, the degree of saponification was 97.5 mol%, and the ethylene content was 4.2 mol%.

[0307] (Synthesis Example 3-4) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin (PVA3-3) was synthesized in the same manner as in Synthesis Example 3-2. The degree of saponification of this PVA was 88.7 mol%, and the average degree of polymerization was 1,780.

[0308] (Synthesis Examples 3-5) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin (PVA3-4) was synthesized in the same manner as in Synthesis Example 3-3. The degree of saponification of the PVA was 98.1 mol%, the average degree of polymerization was 1,680, and the ethylene content was 4.1 mol%.

[0309] [Example 3-1] Aqueous emulsions were prepared from the obtained PVA3-1 using the following method, and the presence or absence of aggregate formation, normal adhesion performance, and coatability were evaluated.

[0310] <Preparation of aqueous emulsion> In a 1-liter glass polymerization vessel equipped with a reflux condenser, dropping funnel, thermometer, and nitrogen inlet, 275 g of deionized water was charged and heated to 85°C. 20.9 g of PVA-1 was dispersed and stirred for 45 minutes to dissolve. 0.3 g of sodium acetate was then added and mixed to dissolve. Next, the aqueous solution containing the dissolved PVA-1 was cooled, purged with nitrogen, and heated to 60°C while stirring at 200 rpm. After adding 2.4 g of a 20% by mass aqueous solution of tartaric acid and 3.2 g of a 5% by mass hydrogen peroxide solution in shots, 27 g of vinyl acetate was charged and polymerization was started. After 30 minutes of polymerization, the completion of the initial polymerization (residual vinyl acetate amount less than 1%) was confirmed. After adding 1 g of a 10% by mass aqueous solution of tartaric acid and 3.2 g of 5% by mass hydrogen peroxide solution in a shot, 251 g of vinyl acetate was continuously added over 2 hours, and the polymerization was completed by maintaining the polymerization temperature at 80°C to obtain a polyvinyl acetate emulsion (Em-1) with a solid content concentration of 49.8% by mass.

[0311] <Amount of aggregates produced> 500 g of the aqueous emulsion obtained in the examples and reference examples was filtered through a 60-mesh wire mesh, and the filtration residue was weighed and evaluated as follows. A: The filtration residue is less than 1.0% by mass. B: The filtration residue is 1.0% by mass or more and less than 2.5% by mass. C: The filtration residue is 2.5% by mass or more and less than 5.0% by mass. D: The filtration residue is 5.0% by mass or more, making filtration difficult.

[0312] <Normal adhesion> The normal adhesion was evaluated in accordance with JIS K 6852 (1994). (Adhesion conditions) Adherent material: Tsuga / Hemlock Coating amount: 150g / m 2 (Both sides coated) Crimping conditions: 20°C, 24 hours, pressure 10 kg / cm² 2 (Measurement conditions) Test specimens cured for 7 days at 20°C and 65% RH were subjected to a compression shear test to determine the adhesive strength (unit: kgf / cm²). 2 ) was measured.

[0313] <Applicability> 0.8g of aqueous emulsion was dropped onto a 25mm wide, 20cm long piece of birch wood, rubbed four times with a rubber roller, and the results were observed. The results were evaluated on a four-point scale from A to D according to the following criteria. A: It is uniformly applied to the entire surface of the birch wood, and no aggregates are formed. B: Uniformly coated over more than half the surface area of ​​the birch wood, with no aggregation or peeling of the coated surface. C: Coated over more than half the surface area of ​​the birch wood, with aggregation occurring and peeling of the coated surface. D: Applied to less than half the surface area of ​​the birch wood, resulting in agglomeration and peeling of the coated surface.

[0314] [Example 3-2, Reference Examples 3-1 and 3-2] Aqueous emulsions were prepared in the same manner as in Example 3-1, except that PVA-2, PVA-3, and PVA-4 were used instead of copolymer 1. The amount of aggregates formed, normal adhesion, and coatability of the obtained aqueous emulsions (Em-2 to Em-4) were evaluated according to the method described above, and the results are summarized in Table 4.

[0315] [Table 4]

[0316] The aqueous emulsions obtained using the PVA from Examples 3-1 and 3-2 as dispersion stabilizers for emulsion polymerization did not form aggregates, and their normal adhesion was comparable to that of Reference Examples 3-1 and 3-2, respectively, demonstrating similar levels of adhesive strength. Furthermore, the applicability, an important indicator when used as an adhesive, was also sufficient, contributing to the conservation of petroleum resources and the mitigation of global warming.

[0317] (Synthesis Example 4-2) <Polyvinyl alcohol-based polymer> Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method. This mixture was then saponified with an alkaline catalyst as a methanol solution, and dried to obtain PVA (PVA4-1). The average degree of polymerization of this PVA, obtained by changing the manufacturing conditions (polymerization conditions, saponification conditions) from Synthesis Example 3-2 within a desired range, was 1700, and the degree of saponification was 98.5 mol%.

[0318] (Synthesis Example 4-3) Using a uniform mixture of 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate as raw materials, PVA (PVA4-2) was obtained in the same manner as in Synthesis Example 4-2. The average degree of polymerization of this PVA was 2400, and the degree of saponification was 88.0 mol%.

[0319] (Synthesis Example 4-4) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin pellets (PVA4-3) were synthesized in the same manner as in Synthesis Example 4-2. The degree of saponification of this PVA was 98.5 mol%, and the average degree of polymerization was 1700.

[0320] (Synthesis Examples 4-5) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin pellets (PVA4-4) were synthesized in the same manner as in Synthesis Example 4-3. The degree of saponification of this PVA was 88.0 mol%, and the average degree of polymerization was 2400.

[0321] [Examples 4-1 to 4-3, Reference Examples 4-1 to 4-3] The obtained PVA4-1 to PVA4-4 samples were evaluated as coating agents by measuring dust removal procedures, room temperature germination, germination tests, accelerated aging tests, and flow fluidity using the methods described below. The results are shown in the table.

[0322] (Soybean seed processing) The seed coating compositions were prepared according to Table 5. Soybean seeds were coated with Acceleron TM The package (containing Monsanto Company, metalaxyl, pyraclostrobin, imidacloprid and fluxapyroxad), is treated with a base of Color Coat Red and water, and Acceleron TM The package achieved a rate of 5.8 fl. oz / cwt. 15.64 mL of slurry was applied to 2400 g of seeds.

[0323] [Table 5]

[0324] (Dust removal procedure) Dried and processed soybean seeds were placed in a closed-system container equipped with a filter and stirred and vibrated under vacuum. Air was introduced into the container and discharged through the filter to remove dust. The amount of dust on the filter was measured and the results are shown in Table 6 below. The seed coating compositions of Examples 4-1 and 4-2 produced a low amount of dust and were found to be comparable to Reference Examples 4-1 and 4-2, respectively.

[0325] [Table 6]

[0326] (Germination at room temperature) This test was used to determine the maximum germination capacity of treated and untreated seeds. Four sets of 100 seeds were prepared, planted on moistened crepe cellulose paper, and left at 25°C for 7 days. The seedlings were then evaluated as "normal," "abnormal," or "dead" according to AOSA rules (Association of Official Seed Analysts rules). The "normal" germination percentage was determined by subtracting the "abnormal" or "dead" seeds from the average number of seeds that germinated during the test period, and then dividing the result by 100 times the original total number of seeds. The results are shown in Table 7 below. The seed coating compositions of Examples 4-1 and 4-2 did not have a harmful effect on germination rates under ideal conditions and were found to be comparable to Reference Examples 4-1 and 4-2, respectively.

[0327] [Table 7]

[0328] (Low-temperature germination test) This test is designed to measure the ability of seeds to germinate under adverse conditions associated with high soil moisture, low soil temperature, and microbial activity. Four sets of 100 seeds each were prepared, planted on moistened crepe cellulose paper, and covered with sand. The cover trays were left at 10°C for 7 days, then moved to 25°C for 4 days. After that, the seedlings were evaluated as "normal," "abnormal," or "dead" according to AOSA rules, taking vitality into consideration. The percentage of "normal" germination was determined by subtracting the "abnormal" or "dead" seeds from the average number of seeds that germinated during the test period, and then dividing the result by the original total number of seeds (100 times). The results are shown in Table 8 below. The results of the low-temperature germination test confirmed that the seed coating compositions of Examples 4-1 and 4-2 were comparable to Reference Examples 4-1 and 4-2 in terms of the percentage of normal seed germination.

[0329] [Table 8]

[0330] (Accelerated aging test) The seeds were weighed and placed in a water-jacketed chamber, maintained at 43°C and high humidity for 72 hours. Four sets of 100 seeds each were prepared, planted on moistened crepe cellulose paper, and covered with sand. The planted cover trays were left at 25°C for 7 days, after which normal seedlings were evaluated according to AOSA rules. The "normal" germination percentage was determined by subtracting any "abnormal" or "dead" seeds from the average number of seeds that germinated during the test period, and then dividing the result by the original total number of seeds by 100. The results are shown in Table 9 below. The seed coating compositions of Examples 4-1 and 4-2 did not reduce germination and were found to be comparable to Reference Examples 4-1 and 4-2, respectively.

[0331] [Table 9]

[0332] (Flow liquidity) The soybean drying flow was measured as the time it took for 1200g of seeds (four 300g sets) to flow through a funnel at 56% relative humidity and 25°C. Adding a coating to the soybeans tended to significantly slow down the seed flow, which is not a desired characteristic. As shown in Table 9, the use of the seed coating composition according to the present invention was found to be comparable in effectiveness and speed to the seeds of Reference Examples 4-1 and 4-2, respectively.

[0333] Seed bridging occurs when seeds exiting the coater are collected in a storage hopper and compressed by opposing seeds. This presents challenges to seed processing facilities in terms of equipment disruption, labor, and time. As shown in Table 10, the use of the seed coating composition according to the present invention did not show a tendency for bridging and was found to be comparable to Reference Examples 4-1 and 4-2, respectively.

[0334] [Table 10]

[0335] (Synthesis Example 5-2) <Dispersion stabilizer for suspension polymerization> Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method with acetaldehyde as a chain transfer agent. This mixture was then saponified with an alkaline catalyst as a methanol solution, and dried to obtain PVA (PVA5-1). The average degree of polymerization of this PVA was 750, and the degree of saponification was 72.0 mol%.

[0336] (Synthesis Example 5-3) Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method. This mixture was then saponified with an alkaline catalyst as a methanol solution, and dried to obtain PVA (PVA5-2). The average degree of polymerization of this PVA, obtained by changing the manufacturing conditions (polymerization conditions, saponification conditions) from Synthesis Example 3-2 within a desired range, was 2400, and the degree of saponification was 80.0 mol%.

[0337] (Synthesis Example 5-4) PVA (PVA5-3) was synthesized using conventional petroleum-derived vinyl acetate as the raw material, in the same manner as in Synthesis Example 5-2. The average degree of polymerization of this PVA was 750, and the degree of saponification was 72.0 mol%.

[0338] (Synthesis Example 5-5) PVA (PVA5-4) was synthesized using conventional petroleum-derived vinyl acetate as the raw material, in the same manner as in Synthesis Example 5-3. The average degree of polymerization of this PVA was 2400, and the degree of saponification was 80.0 mol%.

[0339] [Table 11]

[0340] [Examples 5-1 and 5-2, Reference Examples 5-1 and 5-2] The obtained PVA5-1 to PVA5-4 were subjected to suspension polymerization of vinyl chloride using the method described below. The resulting vinyl chloride polymer particles were then evaluated for average particle size, coarse particle content, and plasticizer absorption. The evaluation results are shown in Table 12.

[0341] (Suspension polymerization of vinyl chloride) The vinyl alcohol copolymer obtained above was dissolved in deionized water in an amount equivalent to 800 ppm relative to vinyl chloride to prepare an aqueous dispersion stabilizer solution. 1150 g of this aqueous dispersion stabilizer solution was placed in a 5 L autoclave. Next, 1.5 g of a 70% toluene solution of diisopropyl peroxydicarbonate was placed in the autoclave. The autoclave was degassed to remove oxygen until the pressure inside the autoclave reached 0.0067 MPa. Then, 1000 g of vinyl chloride was placed in the autoclave, and the contents of the autoclave were heated to 57°C and polymerization was started under stirring. The pressure inside the autoclave at the start of polymerization was 0.83 MPa. After 7 hours from the start of polymerization, when the pressure inside the autoclave reached 0.44 MPa, polymerization was stopped and unreacted vinyl chloride was removed. The polymerization slurry was then removed and dried overnight at 65°C to obtain vinyl chloride polymer particles.

[0342] (Evaluation of vinyl chloride polymer particles) (1) Average particle size of vinyl chloride polymer particles Using a wire mesh based on the Tyler mesh standard, the particle size distribution was measured by dry sieving analysis, and the results were plotted on the Rosin-Rammler distribution formula to determine the average particle size (d p50 The median diameter was calculated.

[0343] (2) Amount of coarse vinyl chloride polymer particles The content of JIS standard 42-mesh sieve ON is expressed in mass percent. A smaller number indicates fewer coarse particles and better polymerization stability.

[0344] (3) Plasticizer absorption (CPA) The mass of a 5 mL syringe filled with 0.02 g of absorbent cotton was weighed (denoted as A(g)), 0.5 g of polyvinyl chloride polymer particles were added to it and weighed (denoted as B(g)), 1 g of dioctyl phthalate (DOP) was added and allowed to stand for 15 minutes, then centrifuged at 3000 rpm for 40 minutes and weighed (denoted as C(g)). The plasticizer absorption (%) was then calculated using the following formula. Plasticizer absorption (%) = 100 × [{(CA) / (BA)} - 1]

[0345] [Table 12] The PVA resins of Examples 5-1 and 5-2 were found to have comparable performance as dispersion stabilizers for suspension polymerization, with average particle size, coarse particle content, and plasticizer absorption values ​​to those of Reference Examples 5-1 and 5-2. Furthermore, they can contribute to the conservation of petroleum resources and the mitigation of global warming.

[0346] (Synthesis Example 6-2) <Dispersion stabilizer for suspension polymerization> Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method. This mixture was then saponified with an alkaline catalyst as a methanol solution, and dried to obtain PVA (PVA6-1). The average degree of polymerization of this PVA, obtained by changing the manufacturing conditions (polymerization conditions, saponification conditions) from Synthesis Example 3-2 within a desired range, was 300, and the degree of saponification was 55.0 mol%.

[0347] (Synthesis Example 6-3) Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method using 3-mercaptopropionic acid (3-MPA) as a chain transfer agent. This was then saponified using an alkaline catalyst in a methanol solution and dried to obtain PVA (PVA6-2). The average degree of polymerization of this PVA was 500, and the degree of saponification was 40.0 mol%.

[0348] (Synthesis Example 6-4) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin (PVA6-3) was synthesized in the same manner as in Synthesis Example 6-2. The average degree of polymerization of this PVA was 300, and the degree of saponification was 55.0 mol%.

[0349] (Synthesis Example 6-5) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin pellets (PVA6-4) were synthesized in the same manner as in Synthesis Example 6-3. The average degree of polymerization of this PVA was 500, and the degree of saponification was 40.0 mol%.

[0350] (Synthesis Example 6-6) <Dispersion stabilizer for suspension polymerization> Polyvinyl acetate was synthesized using conventional petroleum-derived vinyl acetate as the raw material, following a standard method. This was then saponified using an alkaline catalyst in a methanol solution, and dried to obtain PVA (PVA6-5). The average degree of polymerization of this PVA was 2000, and the degree of saponification was 80 mol%.

[0351] [Table 13]

[0352] [Examples 6-1 and 6-2, Reference Examples 6-1 and 6-2] The obtained PVA6-1 to PVA6-4 were subjected to suspension polymerization of vinyl chloride using the method described below. The resulting vinyl chloride polymer particles were then evaluated for (1) average particle size, (2) plasticizer absorption, (3) demonomerization properties, and (4) fish eye. The evaluation results are shown in Table 14.

[0353] [Example 1 of preparation of aqueous solution of dispersion stabilizer for suspension polymerization] PVA, methanol, and distilled water were mixed so that the concentration of PVA6-1 or PVA6-3 as shown in Table 13 was 40% by mass and the concentration of methanol was 5% by mass. The mixture was stirred with a magnetic stirrer at room temperature for 2 hours to obtain an aqueous solution of dispersion stabilizing agent for suspension polymerization.

[0354] [Example 2 of preparation of aqueous solution of dispersion stabilizer for suspension polymerization] A mixture of 5% by mass PVA (PVA) and distilled water, with concentrations of PVA6-2 and PVA6-4 as shown in Table 13, was stirred with a magnetic stirrer at room temperature for 2 hours to obtain an aqueous solution of dispersion stabilizing agent for suspension polymerization.

[0355] (Suspension polymerization of vinyl chloride) In a 5L autoclave, 100 parts of a deionized aqueous solution of a suspension polymerization dispersion stabilizer (PVA6-5) with a viscosity-average degree of polymerization of 2000 and a degree of saponification of 80 mol% was added so that it was 1000 ppm relative to the vinyl chloride monomer. The aqueous solution of the suspension polymerization dispersion stabilizer obtained in Preparation Example 1 was then added so that the amount of PVA6-1 in the aqueous solution of the dispersion stabilizer was 200 ppm relative to the vinyl chloride monomer, and deionized water was added until the total amount of deionized water added was 1640 parts. Next, 1.07 parts of a 70% toluene solution of di(2-ethylhexyl)peroxydicarbonate was added to the autoclave. After introducing nitrogen into the autoclave to bring the pressure down to 0.2 MPa, and then purging the introduced nitrogen, this process was repeated a total of five times to thoroughly purge the autoclave with nitrogen and remove oxygen. Then, 940 parts of vinyl chloride were charged into the autoclave, and the contents were heated to 65°C. Polymerization of the vinyl chloride monomer was started under stirring. The pressure inside the autoclave at the start of polymerization was 1.05 MPa. Approximately 3 hours after the start of polymerization, when the pressure inside the autoclave reached 0.70 MPa, the polymerization was stopped, unreacted vinyl chloride monomers were removed, and the polymerized product was taken out and dried at 65°C for 16 hours to obtain vinyl chloride polymer particles.

[0356] (Evaluation of vinyl chloride polymer particles) (1) Average particle size of vinyl chloride polymer particles Using a wire mesh based on the Tyler mesh standard, the particle size distribution was measured by dry sieving analysis, and the results were plotted on the Rosin-Rammler distribution formula to determine the average particle size (d p50 The median diameter was calculated.

[0357] (2) Plasticizer absorption The mass of a 5 mL syringe filled with 0.02 g of absorbent cotton was weighed (denoted as A(g)), 0.5 g of polyvinyl chloride polymer particles were added to it and weighed (denoted as B(g)), 1 g of dioctyl phthalate (DOP) was added and allowed to stand for 15 minutes, then centrifuged at 3000 rpm for 40 minutes and weighed (denoted as C(g)). The plasticizer absorption (%) was then calculated using the following formula. Plasticizer absorption (%) = 100 × [{(CA) / (BA)} - 1]

[0358] (3) Demonomerization (residual monomer content) After extracting the polymerization reaction product from the suspension polymerization of vinyl chloride, the product was dried at 75°C for 1 hour and 3 hours. The amount of residual monomer at each time point was measured by headspace gas chromatography, and the residual monomer ratio was determined using the following formula. Residual monomer percentage = (Amount of residual monomer after 3 hours of drying / Amount of residual monomer after 1 hour of drying) × 100 A smaller value indicates that a larger proportion of the monomer remaining in the vinyl chloride polymer particles has been removed by drying between 1 hour and 3 hours of drying, i.e., within 2 hours. This value serves as an indicator of how easily the remaining monomer can be removed, i.e., the demonomerization ability.

[0359] (4) Fisheye measurement 100 parts of the obtained vinyl chloride polymer particles, 35 parts of DOP (dioctyl phthalate), 5 parts of tribasic lead sulfate, and 1 part of zinc stearate were mixed using a roll mixer at 150°C for 7 minutes to produce a 0.1 mm thick sheet, and the number of fish eyes per 100 mm x 100 mm of the sheet was measured.

[0360] [Table 14]

[0361] The PVA resins of Examples 6-1 and 6-2 were found to have comparable performance as dispersion stabilizers for suspension polymerization, with average particle size of vinyl chloride polymer particles, plasticizer absorption, demonomerization properties, and fisheye values ​​to those of Reference Examples 6-1 and 6-2. Furthermore, they can contribute to the conservation of petroleum resources and the mitigation of global warming.

[0362] (Synthesis Example 7-2) Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method. This mixture was then saponified using an alkaline catalyst as a methanol solution, and dried to obtain PVA (PVA7-1). The average degree of polymerization of this PVA, obtained by changing the manufacturing conditions (saponification conditions) from Synthesis Example 3-2 within a desired range, was 1,750, and the degree of saponification was 98.5 mol%.

[0363] (Synthesis Example 7-3) PVA (PVA7-2) was obtained using the same method as in Synthesis Example 7-2, except that 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate were uniformly mixed as raw materials and copolymerized with ordinary petroleum-derived ethylene. The average degree of polymerization of this PVA was 1,720, the degree of saponification was 97.5 mol%, and the ethylene unit content was 4.2 mol%.

[0364] (Synthesis Example 7-4) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin (PVA7-3) was synthesized in the same manner as in Synthesis Example 7-2. The degree of saponification of this PVA was 98.7 mol%, and the average degree of polymerization was 1,780.

[0365] (Synthesis Example 7-5) Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin (PVA7-4) was synthesized in the same manner as in Synthesis Example 7-3. The degree of saponification of this PVA was 98.1 mol%, the average degree of polymerization was 1,680, and the ethylene content was 4.1 mol%.

[0366] (Oxygen gas barrier properties) The multilayer structures obtained in the examples and comparative examples were conditioned at 20°C and 85% RH for 5 days, and then the oxygen permeability (cc / m³) was measured using an oxygen permeability measuring device (MOCON OX-TRAN2 / 21, manufactured by MOCON). 2 We measured (day·atm). Temperature: 20℃ Humidity on the oxygen supply side: 85%RH Humidity on the carrier gas side: 85%RH Carrier gas flow rate: 10 mL / min Oxygen pressure: 1.0 atm Carrier gas pressure: 1.0 atm

[0367] [Example 7-1] (Manufacturing of multilayer structures) The obtained PVA7-1 was used to fabricate a multilayer structure using the method described below, and its oxygen gas barrier properties (oxygen permeability) were evaluated. 100 parts by mass of the obtained vinyl alcohol polymer were added to water to prepare an aqueous solution (coating agent) with a concentration of 7% by mass of the vinyl alcohol polymer, and then allowed to stand for 1 hour at 20°C and 60% RH. The anchor coating agent (adhesive) was applied to a layer (D) of a 15 μm thick stretched polyethylene terephthalate (OPET) film (substrate) to form an adhesive component layer on the surface of the OPET film. Using a gravure coater, the coating agent obtained above was applied to the surface of the adhesive component layer at 40°C and then dried at 120°C to form layer (C). To promote the reaction of the anchor coating agent, the film was further heat-treated at 160°C for 120 seconds to obtain a multilayer structure. The thickness of layer (C) was 2 μm. The oxygen permeability of the obtained multilayer structure is shown in Table 15.

[0368] [Example 7-2, Reference Examples 7-1 and 7-2] A multilayer structure was fabricated in the same manner as in Example 7-1, except that PVA7-2, PVA7-3, and PVA7-4 were used instead of PVA7-1. The oxygen permeability of the obtained multilayer structure was evaluated according to the method described above, and the results are summarized in Table 4.

[0369] [Table 15]

[0370] The multilayer structures containing PVA in Examples 7-1 and 7-2 were found to have oxygen gas barrier properties comparable to those of Reference Examples 7-1 and 7-2, respectively, and were confirmed to possess a similar level of barrier properties. The multilayer structures of the present invention and the packaging materials comprising them have excellent oxygen gas barrier properties and can contribute to the conservation of petroleum resources and the mitigation of global warming.

[0371] (Synthesis Example 8-2) Using a uniform mixture of 50 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 50 parts of ordinary petroleum-derived vinyl acetate as raw materials, polyvinyl acetate was synthesized according to a conventional method. This mixture was then saponified with an alkaline catalyst as a methanol solution, and dried to obtain PVA (PVA8-1). The average degree of polymerization of this PVA, obtained by changing the manufacturing conditions (saponification conditions) from Synthesis Example 3-2 within a desired range, was 1,750, and the degree of saponification was 98.5 mol%.

[0372] (Synthesis Example 8-3) PVA (PVA8-2) was obtained using the same method as in Synthesis Example 8-2, except that 30 parts of plant-derived vinyl acetate obtained in Synthesis Example 1-1 and 70 parts of ordinary petroleum-derived vinyl acetate were uniformly mixed as raw materials and copolymerized with ordinary petroleum-derived ethylene. The average degree of polymerization of this PVA was 1,720, the degree of saponification was 97.5 mol%, and the ethylene unit content was 4.2 mol%.

[0373] Using ordinary petroleum-derived vinyl acetate as the raw material, PVA resin (PVA8-3) was synthesized in the same manner as in Synthesis Example 8-2. The degree of saponification of this PVA was 98.7 mol%, and the average degree of polymerization was 1,780.

[0374] (Synthesis Example 8-5) Using ordinary petroleum-derived vinyl acetate as the raw material, a PVA resin (PVA8-4) was synthesized in the same manner as in Synthesis Example 8-3. The degree of saponification of this PVA was 98.1 mol%, the average degree of polymerization was 1,680, and the ethylene unit content was 4.1 mol%.

[0375] [Examples 8-1 and 8-2, Reference Examples 8-1 and 8-2] The obtained PVA8-1 to PVA8-4 were heated and dissolved in hot water at 95°C for 2 hours to prepare a coating agent with a solid content of 6%. The coating agent was evaluated using the method described below. The results are shown in Table 16.

[0376] [Tests on the production of coated paper using coating agents] Using a wire bar, a coating agent was applied by hand to 64 gsm glassine paper at 20°C. The paper was then dried at 105°C for 1 minute using a cylinder-type rotary dryer. The coating amount, calculated based on solid content, was 1.0 gsm (one side). The resulting coated paper was conditioned at 20°C and 65% RH for 72 hours, after which its physical properties were measured.

[0377] [Water resistance test of coated paper] Approximately 0.1 g of deionized water at 20°C was dropped onto the surface of the coated paper manufactured using the method described above (the coated surface of the coating agent). The paper was then rubbed with a fingertip, and the state of dissolution of the coating agent was observed and evaluated according to the following criteria. ○ - Excellent water resistance and no slimy feeling. △ - A portion of the coating agent emulsifies. × - The coating agent dissolves.

[0378] [Evaluation for release paper applications: Air permeability resistance measurement] The air permeability resistance of coated paper was measured using a Wang Ken type slipperiness air permeability tester in accordance with JIS P 8117:2009.

[0379] [Evaluation for release paper applications: Toluene barrier property test] After applying colored toluene (red), which is a solution of red food coloring, to the coated surface of coated paper (5 x 5 cm), the degree of bleed-through to the reverse side (uncoated surface) (small red spots or complete coloring of the coated surface) was evaluated according to the following criteria. 5. No spots on the reverse side. 4. Spots appear (1 or 2 spots) 3. Numerous spots appear (approximately 10-20% of the toluene-coated surface). 2. Approximately 50% of the coated surface is colored. 1. The entire coated surface is colored.

[0380] [Evaluation for oil-resistant paper applications: KIT test, folding KIT test] KIT tests were conducted on the flat and folded surfaces of the coated paper based on TAPPI No. T559cm-02. Evaluation was performed visually. The KIT value of commercially available oil-resistant paper using fluororesin is typically 5th grade or higher, and an oil resistance of 5th grade or higher is sufficient for general use. Therefore, it is preferable for coated paper to have an oil resistance of 5th grade or higher, 7th grade or higher is preferable for applications requiring higher oil resistance, and 10th grade or higher is even preferable.

[0381] In the KIT test of the folded section, the coated paper was folded in half with the coated surface facing outwards, and a pressure of 2.5 kgf / cm was applied to the folded section from above, with a width of 1.0 mm, a depth of 0.7 mm, and a pressure of 2.5 kgf / cm². 2 Under the condition of 1 second, the paper was pressed to create a complete crease, then the coated paper was unfolded, and the oil resistance of the creased area was measured using TAPPI No. T559cm-02. The measurement was performed visually.

[0382] [Table 16]

[0383] The PVA-containing coating agents of Examples 8-1 and 8-2 were found to have comparable performance to those of Reference Examples 8-1 and 8-2, respectively, in terms of the physical properties of the coated paper. The paper coating agent of the present invention, and the paper coated therewith, have excellent barrier properties and oil resistance, and can contribute to the conservation of petroleum resources and the mitigation of global warming.

Claims

1. A vinyl alcohol polymer (X) obtained by polymerizing and saponifying a plant-derived vinyl ester monomer (A) and a petroleum-derived vinyl ester monomer (B), wherein the molar ratio of (A) / (B) is 5 / 95 to 100 / 0.

2. The vinyl alcohol-based polymer (X) according to claim 1, further comprising ethylene units, wherein the content of ethylene units is 1 mol% or more and less than 20 mol%.

3. A slurry additive comprising the vinyl alcohol-based polymer (X) described in claim 1 or 2.

4. Drilling slurry containing the slurry additive described in claim 3.

5. Furthermore, the drilling slurry according to claim 4, further containing water and bentonite.

6. A cement slurry containing the slurry additive described in claim 3.

7. Furthermore, the cement slurry according to claim 6 further contains a liquid agent and a curable powder.

8. comprising the vinyl alcohol-based polymer (X) described in claim 1 or 2, A ground sealant for underground treatment, with a molar ratio of (A) / (B) of 5 / 95 to 90 / 10.

9. The underground treatment sealant according to claim 8, wherein the vinyl alcohol-based polymer (X) comprises another unsaturated monomer (C) copolymerizable with a vinyl ester monomer.

10. Furthermore, the ground treatment sealant according to claim 8 or 9, further comprising a plasticizer.

11. The material comprises a layer (C) containing the vinyl alcohol polymer (X) described in claim 1 or 2, and a layer (D) containing a resin, A multilayer structure in which the resin is at least one resin selected from the group consisting of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride (PVC) resin, ABS resin, polylactic acid (PLA) resin, polybutylene succinate (PBS) resin, polyhydroxyalkanoate (PHA) resin, polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin, starch, and cellulose.

12. The process includes the steps of preparing an aqueous solution containing the vinyl alcohol polymer (X) to obtain a coating agent, and applying the coating agent to the surface of a resin-containing substrate. The method for producing a multilayer structure according to claim 11, wherein the resin is at least one resin selected from the group consisting of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride (PVC) resin, ABS resin, polylactic acid (PLA) resin, polybutylene succinate (PBS) resin, polyhydroxyalkanoate (PHA) resin, polyhydroxybutyrate / hydroxyhexanoate (PHBH) resin, starch, and cellulose.

13. A packaging material comprising the multilayer structure described in claim 11.

14. A paper coating agent comprising the vinyl alcohol-based polymer (X) described in claim 1 or 2.

15. Coated paper comprising paper coated with the paper coating agent described in claim 14.

16. The coated paper according to claim 15, wherein the base paper is a release liner.

17. The coated paper according to claim 15, which is oil-resistant paper.

18. A seed coating composition comprising the vinyl alcohol-based polymer (X) described in claim 1 or 2.

19. Furthermore, the seed coating composition according to claim 18 further comprises one or more hydrophobic pesticides.

20. An aqueous emulsion comprising a dispersant and a dispersed phase, The dispersed phase comprises a polymer (Y1) containing ethylenically unsaturated monomer units, An aqueous emulsion wherein the dispersant comprises the vinyl alcohol-based polymer (X) described in claim 1 or 2.

21. The aqueous emulsion according to claim 20, wherein the polymer (Y1) containing ethylenically unsaturated monomer units is a polymer having specific units derived from at least one selected from the group consisting of vinyl ester monomers, (meth)acrylic acid ester monomers, styrene monomers, and diene monomers, and the content of the aforementioned units relative to the total monomer units of the polymer is 70% by mass or more.

22. The aqueous emulsion according to claim 20 or 21, further containing a polyvalent isocyanate compound.

23. An adhesive comprising the aqueous emulsion described in any one of claims 20 to 22.

24. A dispersion stabilizer for suspension polymerization of vinyl compounds, comprising the vinyl alcohol polymer (X) described in claim 1 or 2.

25. A method for producing a vinyl resin, comprising the step of performing suspension polymerization of a vinyl compound in the presence of the suspension polymerization dispersion stabilizer described in claim 24.

26. The process includes carrying out suspension polymerization of a vinyl compound in the presence of the aforementioned suspension polymerization dispersion stabilizer and a further dispersion stabilization aid. The method for producing a vinyl resin according to claim 25, wherein the dispersion stabilizing agent comprises a vinyl alcohol-based polymer (Y2) having a degree of saponification of less than 65 mol%.

27. comprising the vinyl alcohol-based polymer (X) described in claim 1 or 2, A dispersion stabilizing aid for suspension polymerization of vinyl compounds, wherein the degree of saponification of the vinyl alcohol polymer (X) is 20 mol% or more and less than 60 mol%.

28. The process includes carrying out suspension polymerization of a vinyl compound in the presence of the suspension polymerization dispersion stabilizer described in claim 27 and the suspension polymerization dispersion stabilizer, A method for producing a vinyl resin, wherein the aforementioned suspension polymerization dispersion stabilizer contains a vinyl alcohol-based polymer (Y3) with a degree of saponification of 65 mol% or more and a viscosity-average degree of polymerization of 600 or more.

29. A method for producing a vinyl resin according to claim 28, wherein the mass ratio of the dispersion stabilizer to the dispersion stabilizing aid (dispersion stabilizer / dispersion stabilizing aid) is 95 / 5 to 20 / 80.

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