Cross-linked polyolefin foam, and odor reducing agent for said cross-linked polyolefin foam.

Abstract

To provide a technology that can reduce the generation of odor components in low-density cross-linked polyolefin foams. [Solution] This technology provides a crosslinked polyolefin foam obtained by crosslinking a polyolefin resin, which contains a wood filler and has a density of 60 kg / m³. 3 The following cross-linked polyolefin foam is provided. The cross-linked polyolefin foam according to this technology can use petroleum resin as a raw material. In this case, C9-based petroleum resin can be used as the petroleum resin. Hydrogenated petroleum resin can also be used as the petroleum resin. The cross-linked polyolefin foam according to this technology may also contain an inorganic filler. This technology also provides an odor-reducing agent for cross-linked polyolefin foam obtained by cross-linking a polyolefin resin, which contains a wood filler and has a density of 60 kg / m³. 3 We also provide odor reducers for the following cross-linked polyolefin foams.

Description

[Technical Field]

[0001] This technology relates to cross-linked polyolefin foams. More specifically, it relates to cross-linked polyolefin foams in which the generation of odor components is suppressed, and to odor-reducing agents for said cross-linked polyolefin foams. [Background technology]

[0002] Traditionally, resin foams have been used in a variety of applications due to their excellent cushioning, heat insulation, water repellency, moisture resistance, and sound insulation properties, and various technological improvements have been made to suit each application. In recent years, in order to contribute to the formation of a sustainable society, the technology of using biomass raw materials in resin foams as a so-called carbon-neutral renewable resource has also attracted attention.

[0003] For example, Patent Document 1 discloses a foaming resin composition containing a polymeric substance, 5 to 100 parts by mass of lignin and 1 to 30 parts by mass of a foaming agent per 100 parts by mass of the polymeric substance. Patent Document 1 proposes a technology for producing a lignin-containing polymer foam using this foaming resin composition, which is not only considered to have a uniform foam structure inside that suppresses unpleasant odors and reduces the amount of carbon dioxide generated when incinerated, but may also be evaluated in the future as having carbon storage properties.

[0004] Furthermore, Patent Document 2 proposes a technology for efficiently obtaining foamed resin sheets by using a foamed resin composition containing specific amounts of polyethylene resin (100 parts by mass), wood-based filler, inorganic filler, and foaming agent, rolling it at a specific temperature to form a sheet, and then repeating the process of winding it onto a calender roll at a different temperature twice. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-254952 [Patent Document 2] Japanese Patent Publication No. 2016-196160 [Overview of the initiative] [Problems that the invention aims to solve]

[0006] In recent years, from the perspective of preventing environmental pollution, there has been a demand to reduce the emission of odor components and volatile organic compounds (VOCs). On the other hand, the use of blowing agents is unavoidable in order to manufacture low-density resin foams, but depending on the type of blowing agent used, odor components such as ammonia may be generated, which can be problematic.

[0007] Therefore, the main objective of this technology is to provide a method that can reduce the generation of odor components in low-density cross-linked polyolefin foams. [Means for solving the problem]

[0008] In order to solve the aforementioned problems, the inventors diligently researched techniques to suppress the generation of odor components from low-density cross-linked polyolefin foams. As a result, they succeeded in reducing the odor components generated from cross-linked polyolefin foams by using wood fillers, and thus completed this technology. In other words, this technology first involves crosslinking a polyolefin resin to obtain a crosslinked polyolefin foam, Contains wood filler, Density is 60 kg / m³ 3 The following cross-linked polyolefin foam is provided. In the cross-linked polyolefin foam according to this technology, petroleum resin can be used as a raw material. In this case, C9-based petroleum resin can be used as the petroleum resin. Alternatively, hydrogenated petroleum resin can be used as the petroleum resin. The cross-linked polyolefin foam related to this technology may also contain inorganic fillers.

[0009] In this technology, the next step is to provide an odor-reducing agent for crosslinked polyolefin foam obtained by crosslinking polyolefin resins, Contains wood filler, Density is 60 kg / m³ 3 The following odor-reducing agents for cross-linked polyolefin foams are provided. Petroleum resin can be used as the raw material for the cross-linked polyolefin foam that is the target of the odor-reducing agent according to this technology. In this case, C9-based petroleum resin can be used as the petroleum resin. Hydrogenated petroleum resin can also be used as the petroleum resin. The cross-linked polyolefin foam targeted by the odor-reducing agent related to this technology may also contain inorganic fillers. [Modes for carrying out the invention]

[0010] The following describes preferred embodiments for implementing this technology. The embodiments described below are examples of typical embodiments of this technology, and any combination of these embodiments is possible. Furthermore, this does not mean that the scope of this technology will be narrowed.

[0011] 1. Cross-linked polyolefin foam The cross-linked polyolefin foam according to this technology contains a polyolefin resin and a wood filler. That is, the cross-linked polyolefin foam according to this technology is a cross-linked foam of a resin composition containing a polyolefin resin and a wood filler. Furthermore, the resin composition for producing the cross-linked polyolefin foam according to this technology (hereinafter also referred to as "the resin composition") may contain a foaming agent, a cross-linking agent, a foaming aid, a lubricant, an inorganic filler, and various other components that can be used in the production of the cross-linked polyolefin foam depending on the purpose. Each component will be described in detail below.

[0012] (1) Resin components The crosslinked polyolefin foam according to the present technology is characterized by using a polyolefin resin as the resin component. Further, in the crosslinked polyolefin foam according to the present technology, as long as the effects and advantages of the present technology are not impaired, it is also possible to use a petroleum resin or other resin components in combination as the resin component.

[0013] (1-1) Polyolefin resin The polyolefin resin that can be used in the crosslinked polyolefin foam according to the present technology is a resin having an olefin component unit as the main component. A resin having an olefin component unit as the main component is a resin containing 50% by mass or more of the olefin component unit. In the present technology, the content of the olefin component unit in the resin is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and it is particularly preferable that the resin component is composed only of a polyolefin resin.

[0014] Examples of the polyolefin resin that can be used in the present technology include polyethylene resins, polypropylene resins, polybutene, polypentene, and copolymers of an olefin monomer and a monomer copolymerizable with the olefin monomer, and these can also be used alone or in combination of two or more.

[0015] Examples of the polyethylene resin include ethylene-vinyl acetate copolymers (EVA), high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (VLDPE), etc., which are ethylene homopolymers; ethylene-propylene random copolymers, ethylene-propylene block copolymers, ethylene-butene block copolymers, ethylene-butene random copolymers, and ethylene-methyl methacrylate copolymers, etc.

[0016] Examples of polypropylene resins include propylene homopolymers such as isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene; propylene-ethylene random copolymers, propylene-ethylene block copolymers, propylene-butene random copolymers, propylene-butene block copolymers, propylene-ethylene-butene terpolymers, propylene-acrylic acid copolymers, and propylene-maleic anhydride copolymers.

[0017] Among these, in this technology, it is preferable to use a polyethylene resin, and among polyethylene resins, it is preferable to use an ethylene-vinyl acetate copolymer (EVA). In this technology, the content of ethylene-vinyl acetate copolymer (EVA) in 100 parts by weight of the polyolefin resin is preferably 50.0 parts by weight or more, more preferably 60.0 parts by weight or more, still more preferably 70.0 parts by weight or more, and particularly preferably 80.0 parts by weight or more. By setting the content of ethylene-vinyl acetate copolymer (EVA) in 100 parts by weight of the polyolefin resin within this range, the flexibility of the produced crosslinked polyolefin foam can be improved.

[0018] (1-2) Petroleum resin The crosslinked polyolefin foam according to this technology can use a petroleum resin as a raw material. By using a petroleum resin, the cell structure of the crosslinked polyolefin foam can be changed to a desired state. When the cell structure changes, for example, in the foam-breaking process during the production of the crosslinked polyolefin foam described later, foam-breaking becomes easier, and it becomes possible to stably obtain a foam with a continuous bubble structure.

[0019] Petroleum resin is a hydrocarbon resin obtained by polymerizing cracked oil fractions (C5 fraction (aliphatic) and C9 fraction (aromatic)) that are by-products when decomposing petroleum in the petroleum refining industry and petrochemical industry. From the perspective of compatibility with polyolefin resins, it is preferable to use C9-based petroleum resin among petroleum resins in the crosslinked polyolefin foam according to this technology.

[0020] Furthermore, in the crosslinked polyolefin foam related to this technology, it is preferable to use hydrogenated petroleum resin among petroleum resins, from the viewpoint of odor, color, thermal stability, weather resistance, and compatibility with polyolefin resins.

[0021] Therefore, it is more preferable to use C9 hydrogenated petroleum resin among petroleum resins for the crosslinked polyolefin foam related to this technology.

[0022] When using C9 hydrogenated petroleum resin, the content of C9 hydrogenated petroleum resin in the resin component can be freely set as long as it does not impair the function and effects of this technology. The lower limit of the content of C9 hydrogenated petroleum resin per 100 parts by weight of polyolefin resin is, for example, 1.0 part by weight or more, preferably 2.0 parts by weight or more, and more preferably 3.0 parts by weight or more. The upper limit of the content of C9 hydrogenated petroleum resin per 100 parts by weight of polyolefin resin is, for example, 10.0 parts by weight or less, preferably 9.0 parts by weight or less, and more preferably 8.0 parts by weight or less.

[0023] (1-3) Other resins The cross-linked polyolefin foam relating to this technology may contain, in addition to the polyolefin resin, other resins, thermoplastic elastomers, thermosetting elastomers, etc., to the extent that they do not impair the purpose or effects of this technology. Examples of resins other than polyolefin resins include thermoplastic resins such as polystyrene resins, polyamide resins, and polyester resins. Examples of thermoplastic elastomers include olefin-based thermoplastic elastomers and styrene-based thermoplastic elastomers. Examples of thermosetting elastomers include synthetic rubbers such as ethylene propylene rubber (EPDM) and natural rubber.

[0024] (2) Wood filler The cross-linked polyolefin foam according to this technology is characterized by the use of wood-based fillers. By using wood-based fillers, odor components generated from the cross-linked polyolefin foam can be reduced.

[0025] The wood filler used in this technology is a granular material mainly composed of cellulose, such as wood, bamboo trunks, branches, and leaves, or pulp, paper, cotton, hemp, rayon, rayon, spun rayon, kenaf, rice husks, and cellulose fibers. More specifically, it is a fibrous component obtained by crushing the raw material, such as tree branches and leaves, in a pulverizer as necessary, and then removing at least some of the essential oils and moisture by, for example, heating with microwaves under reduced pressure (vacuum distillation method) or by removing at least some of the essential oils and moisture with an organic solvent (solvent extraction method). Therefore, the wood filler may contain essential oils and / or moisture.

[0026] The above-described vacuum distillation method can be carried out using, for example, tree branches and leaves as raw materials, and a microwave distillation apparatus as described in International Publication No. 2010 / 098440, etc. In this vacuum distillation method, the pressure inside the distillation tank should be set to 1 to 95 kPa, preferably 5 to 80 kPa, and particularly preferably 10 to 60 kPa. The vapor temperature at this time will be 40 to 100°C.

[0027] The solvent extraction method described above can be carried out, for example, by using tree branches and leaves as raw materials and distilling them using a distillation apparatus with polar solvents such as water, ethanol, methanol, butyl alcohol, ethylene glycol, propylene glycol, glycerin, halogen-containing solvents such as chloroform, ether solvents such as dioxane, carbonyl solvents such as acetone and ethyl acetate, and mixtures thereof, and distilling the distillate (essential oil and purified water) by atmospheric distillation, vacuum distillation, steam distillation, etc.

[0028] After removing at least some of the essential oils and moisture from the tree branches and leaves by vacuum distillation, solvent extraction, etc., a drying process may be carried out to remove moisture at atmospheric pressure. The drying temperature and drying time are not particularly limited, but for example, it may be carried out at 50-80°C for 1-5 hours. The moisture content of the powder obtained after the drying process is not particularly limited, but for example, it is about 3-15% by weight.

[0029] Examples of plants that can be used as raw materials for wood fillers include those belonging to the genus Chamaecyparis in the cypress family, the genus Thuja in the cypress family, the genus Juniper in the cypress family, the genus Cryptomeria in the cypress family, the genus Abies in the pine family, the genus Cedrus in the pine family, the genus Picea in the pine family, the genus Pinus in the pine family, the genus Larix in the pine family, the genus Hemlock in the pine family, the genus Eucalyptus in the Myrtaceae family, the genus Sciadopitys in the Sciadopityaceae family, the genus Torreya in the yew family, and the genus Thuja in the cypress family. Among these, in this technology, the following are preferred: cypress (Thuja or Chamaecyparis obtusa), cedar (Cupressaceae), fir (Abies genus), eucalyptus (Myrtaceae), sciadopitys (Sciadopitys verticillata), and cypress (Thuja genus). From the perspective of being widely distributed in Japan and easily available, cypress (Thuja orientalis), Taiwanese cypress (Thuja orientalis), cedar (Cupressaceae), fir (Abies sachalinensis), eucalyptus (Myrtaceae), sciadopitys (Sciadopitys verticillata), and cypress (Thuja chinensis). It is also possible to use one or more combinations of wood fillers obtained from these plants.

[0030] The content of the wood filler used in this technology in the resin composition can be freely set as long as it does not impair the function and effects of this technology. The lower limit of the content of the wood filler per 100 parts by weight of polyolefin resin in the resin composition is, for example, 0.5 parts by weight or more, preferably 1.0 part by weight or more, and more preferably 1.5 parts by weight or more. By setting the lower limit of the wood filler content within this range, the effect of reducing odor components generated from the cross-linked polyolefin foam can be further improved.

[0031] The upper limit of the wood filler content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 14.0 parts by weight or less, preferably 13.0 parts by weight or less, more preferably 12.0 parts by weight or less, and even more preferably 10.0 parts by weight or less. By setting the upper limit of the wood filler content within this range, the foaming properties during the production of crosslinked polyolefin foam can be improved.

[0032] The average particle size of the wood filler used in this technology can be freely set as long as it does not impair the function or effect of this technology. The lower limit of the average particle size of the wood filler is, for example, 1 μm or more, preferably 3 μm or more, and more preferably 5 μm or more. Setting the lower limit of the average particle size of the wood filler within this range improves the workability during the production of cross-linked polyolefin foam.

[0033] The upper limit of the average particle size of the wood filler is, for example, 2000 μm or less, preferably 1500 μm or less, more preferably 1000 μm or less, even more preferably 500 μm or less, even more preferably 100 μm or less, and particularly preferably 50 μm or less. By setting the upper limit of the average particle size of the wood filler within this range, the compression set of the manufactured cross-linked polyolefin foam can be improved.

[0034] (3) Foaming agent The resin composition for producing the crosslinked polyolefin foam according to this technology may contain a blowing agent. As for the blowing agent that can be used in this technology, one or more blowing agents that can be used in polyolefin resin foams can be freely selected and used, as long as they do not impair the purpose or effects of this technology.

[0035] Examples of blowing agents that can be used in this technology include organic or inorganic pyrolysis-type chemical blowing agents. Examples of organic blowing agents include azo compounds such as azodicarbonamide (ADCA), azodicarboxylic acid metal salts (such as barium azodicarboxylic acid), and azobisisobutyronitrile (AIBN); nitroso compounds such as N,N'-dinitrosopentamethylenetetramine (DPT); hydrazine derivatives such as hydrazodicarbonamide, 4,4'-oxybis(benzenesulfonyl hydrazide), and toluenesulfonyl hydrazide (TSH); and semicarbazide compounds such as toluenesulfonyl semicarbazide. Examples of inorganic blowing agents include ammonium carbonate, sodium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and anhydrous monosodium citrate.

[0036] Among these, in this technology, it is preferable to use an organic blowing agent, and among organic blowing agents, it is preferable to use azodicarbonamide (ADCA).

[0037] The amount of blowing agent used in the production of the crosslinked polyolefin foam according to this technology can be freely set as long as it does not impair the purpose and effects of this technology. In this technology, the lower limit of the blowing agent content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 5.0 parts by weight or more, preferably 7.0 parts by weight or more, and more preferably 10.0 parts by weight or more. By setting the lower limit of the blowing agent content in the resin composition within this range, the foaming properties during foam production can be improved, and the physical properties of the foam produced can be improved.

[0038] In this technology, the upper limit of the foaming agent content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 30.0 parts by weight or less, preferably 25.0 parts by weight or less, and more preferably 20.0 parts by weight or less. By setting the upper limit of the foaming agent content in the resin composition within this range, it is possible to suppress molding defects due to excessive foaming and also contribute to cost reduction.

[0039] In this technology, the foaming agent can be used as a masterbatch in which the foaming agent is dispersed in the aforementioned resin component. By using a foaming agent masterbatch, the dispersibility of the foaming agent in the resin component can be improved.

[0040] (4) Crosslinking agent The cross-linked polyolefin foam according to this technology is a cross-linked foam. By performing cross-linking during the manufacturing of the cross-linked polyolefin foam according to this technology, the viscosity of the resin composition (kneaded material) before foaming can be improved, thereby improving foamability. Furthermore, the physical properties of the manufactured foam can be improved.

[0041] The crosslinked polyolefin foam according to this technology can be crosslinked by ionizing radiation irradiation, but it can also be chemically crosslinked using a crosslinking agent. As long as the purpose and effects of this technology are not impaired, one or more crosslinking agents that can be used with polyolefin resin foams can be freely selected and used.

[0042] Examples of crosslinking agents that can be used in this technology include those having chemical structures such as silane groups, peroxides, hydroxyl groups, amide groups, and ester groups. Among these, it is preferable to use organic peroxides as crosslinking agents in this technology.

[0043] Examples of organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, di-t-butylperoxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, and t-dibutylhydroperoxide. Among these, dicumyl peroxide is preferred as the crosslinking agent in this technology.

[0044] The amount of crosslinking agent used in the production of the crosslinked polyolefin foam according to this technology can be freely set as long as it does not impair the purpose and effects of this technology. In this technology, the lower limit of the crosslinking agent content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 0.2 parts by weight or more, preferably 0.3 parts by weight or more, and more preferably 0.5 parts by weight or more. By setting the lower limit of the crosslinking agent content in the resin composition within this range, viscosity can be improved and foaming properties can be enhanced. Furthermore, the mechanical properties of the manufactured foam can be improved.

[0045] In this technology, the upper limit of the crosslinking agent content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 4.0 parts by weight or less, preferably 3.0 parts by weight or less, and more preferably 2.0 parts by weight or less. By setting the upper limit of the crosslinking agent content in the resin composition within this range, cracking and other defects during foaming can be prevented, and moldability can be improved.

[0046] (5) Foaming agent The resin composition for producing the crosslinked polyolefin foam according to this technology may contain a foaming aid. As for the foaming aid that can be used in this technology, one or more foaming aids that can be used in polyolefin resin foams can be freely selected and used, as long as they do not impair the purpose or effects of this technology.

[0047] Examples of foaming agents that can be used in this technology include urea-based additives such as urea, metal oxides, and fatty acid metal salts. Examples of metal oxides include zinc oxide, zinc chloride, zinc acetate, zinc nitrate, lead oxide, dibasic lead phosphite, and tribasic lead sulfate. Examples of fatty acid metal salts include zinc stearate, lead stearate, magnesium stearate, and calcium stearate. Among these, it is preferable to use urea and / or zinc stearate as foaming agents in this technology.

[0048] The amount of foaming aid used in the production of the crosslinked polyolefin foam according to this technology can be freely set as long as it does not impair the purpose and effects of this technology. In this technology, the lower limit of the foaming aid content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 0.01 parts by weight or more, preferably 0.02 parts by weight or more, and more preferably 0.03 parts by weight or more. By setting the lower limit of the foaming aid content in the resin composition within this range, the foaming properties during foam production can be improved and the density of the foam produced can be reduced.

[0049] In this technology, the upper limit of the foaming aid content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 3.0 parts by weight or less, preferably 2.0 parts by weight or less, and more preferably 1.0 part by weight or less. By setting the upper limit of the foaming aid content in the resin composition within this range, it is possible to suppress formation defects due to excessive foaming and also contribute to cost reduction.

[0050] (6) Lubricant The resin composition for producing the crosslinked polyolefin foam according to this technology may contain a lubricant. As long as the purpose and effects of this technology are not impaired, one or more lubricants that can be used in polyolefin resin foams can be freely selected and used. Examples of lubricants that can be used in this technology include stearic acid, zinc stearate, calcium stearate, polyethylene glycol, silicone oil, sorbitan monostearate, sorbitan tristearate, and the like.

[0051] The amount of lubricant used in the production of the crosslinked polyolefin foam according to this technology can be freely set as long as it does not impair the purpose and effects of this technology. In this technology, the lower limit of the lubricant content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 0.1 parts by weight or more, preferably 0.5 parts by weight or more, and more preferably 1.0 part by weight or more. By setting the lower limit of the lubricant content in the resin composition within this range, the workability during foam production can be improved.

[0052] In this technology, the upper limit of the lubricant content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 10.0 parts by weight or less, preferably 8.0 parts by weight or less, and more preferably 7.0 parts by weight or less. By setting the upper limit of the lubricant content in the resin composition within this range, molding defects can be suppressed, and cost reduction can also be achieved.

[0053] (7) Inorganic fillers This technology allows the use of inorganic fillers in addition to the wood fillers mentioned above. By using inorganic fillers in addition to the wood fillers mentioned above, it is possible to manufacture cross-linked polyolefin foams with fine cells, and the amount of resin components can be reduced, which can contribute to cost reduction.

[0054] As inorganic fillers that can be used in this technology, one or more types of fillers that can be used in polyolefin resin foams can be freely selected and used, as long as they do not impair the purpose and effects of this technology. Examples of inorganic fillers that can be used in this technology include calcium carbonate such as heavy calcium carbonate, magnesium carbonate, calcium hydroxide, silicic acid and its salts, clay, talc, mica powder, bentonite, silica, alumina, aluminum silicate, and aluminum powder. Among these, calcium carbonate is preferred in this technology.

[0055] The amount of inorganic filler used in the crosslinked polyolefin foam according to this technology can be freely set as long as it does not impair the purpose and effects of this technology. In this technology, the lower limit of the inorganic filler content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 10.0 parts by weight or more, preferably 12.0 parts by weight or more, and more preferably 15.0 parts by weight or more. By setting the lower limit of the inorganic filler content in the resin composition within this range, cost reduction can be achieved.

[0056] In this technology, the upper limit of the inorganic filler content per 100 parts by weight of polyolefin resin in the resin composition is, for example, 30.0 parts by weight or less, preferably 25.0 parts by weight or less, and more preferably 20.0 parts by weight or less. By setting the upper limit of the inorganic filler content in the resin composition within this range, it is possible to suppress a decrease in the mechanical strength and foamability of the manufactured cross-linked polyolefin foam.

[0057] (8) Others In the production of the crosslinked polyolefin foam according to this technology, one or more components that can be used in the production of polyolefin resin foams may be freely selected and used as other components, as long as they do not impair the purpose or effect of this technology.

[0058] Examples of components that can be used in the production of crosslinked polyolefin foams according to this technology include crosslinking accelerators, foam stabilizers, flame retardants, stabilizers, plasticizers, colorants, antioxidants, dispersants, and ultraviolet absorbers.

[0059] 2. Physical properties of cross-linked polyolefin foams (1) Density The density of the cross-linked polyolefin foam related to this technology is 60 kg / m³ 3 The following applies: The upper limit of the density of the cross-linked polyolefin foam related to this technology is 60 kg / m³, provided that it does not impair the purpose or effect of this technology. 3 The following range can be freely set, but preferably 50 kg / m 3Hereinafter, more preferably 45 kg / m 3 or less.

[0060] The lower limit of the density of the crosslinked polyolefin foam according to the present technology is, for example, 10 kg / m 3 or more, preferably 15 kg / m 3 or more, more preferably 20 kg / m 3 or more, still more preferably 25 kg / m 3 or more. By setting the lower limit of the density of the crosslinked polyolefin foam within this range, it is possible to prevent it from becoming too soft and impart appropriate elasticity.

[0061] In the present technology, the density of the crosslinked polyolefin foam is a value measured in accordance with the method based on JIS K6767.

[0062] (2) 50% Compression stress The 50% compression stress of the crosslinked polyolefin foam according to the present technology can be freely set as long as the object and effect of the present technology are not impaired. In the present technology, as the lower limit of the 50% compression stress of the crosslinked polyolefin foam, for example, 2.0 kPa or more, preferably 3.5 kPa or more, more preferably 4.0 kPa or more. By setting the lower limit of the 50% compression stress of the crosslinked polyolefin foam within this range, it is possible to give the crosslinked polyolefin foam appropriate resilience.

[0063] The upper limit of the 50% compression stress of the crosslinked polyolefin foam according to the present technology can be freely set as long as the object and effect of the present technology are not impaired, but for example, 10. kPa or less, preferably 9.5 kPa or less, more preferably 8.5 kPa or less. By setting the 50% compression stress of the crosslinked polyolefin foam within this range, it is possible to prevent it from becoming too hard and impart appropriate flexibility.

[0064] In the present technology, the 50% compression stress of the crosslinked polyolefin foam is a value measured in accordance with the method based on JIS K6767.

[0065] (3) Compression set The compression set of the crosslinked polyolefin foam according to this technology can be freely set as long as it does not impair the purpose and effects of this technology. In this technology, the upper limit of the compression set of the crosslinked polyolefin foam can be freely set as long as it does not impair the purpose and effects of this technology, but for example, it is 12% or less, preferably 10% or less, more preferably 7% or less, and even more preferably 5% or less. By setting the compression set of the crosslinked polyolefin foam within this range, the durability of the crosslinked polyolefin foam can be improved.

[0066] The lower limit of the compression set of the cross-linked polyolefin foam related to this technology is not particularly limited, but can be set to, for example, 0.5% or more, 1.0% or more, etc.

[0067] In this technology, the compression set of the cross-linked polyolefin foam was measured according to the method based on JIS K6767.

[0068] (4) Bubble morphology The morphology of the cells in the cross-linked polyolefin foam used in this technology is not particularly limited as long as it does not impair the function or effect of this technology. Depending on the application, it may have closed cells or open cells, but open cells are preferable. Open cells have a larger surface area, which allows the wood filler to come into contact with odor components more easily, thus making it easier to exhibit ammonia reduction and VOC reduction effects, which are odor components.

[0069] 3. Method for producing cross-linked polyolefin foam The crosslinked polyolefin foam according to this technology is characterized by its composition, and its manufacturing method is not particularly limited. For example, a method can be employed in which a crosslinking agent and a blowing agent are added to a polyolefin resin and a wood filler, and other additives are optionally added and mixed as needed, and then foamed and molded. Preferably, the manufacturing method of the crosslinked polyolefin foam may be any of the following: a one-stage block foaming method, a two-stage block foaming method, a long-length foaming method using chemical crosslinking, or a long-length foaming method using electron beam crosslinking.

[0070] <Single-block foaming method> The single-stage block foaming method comprises, for example, the following steps (1)-(2). (1) Mixing process A foamable resin composition is prepared by melting and kneading polyolefin resin, wood filler, foaming agent, crosslinking agent, and as needed foaming aids, lubricants, and other optional components at a temperature below the decomposition temperature of the foaming agent using a kneading device such as an extruder, Banbury mixer, kneader, or roll. (2) Foaming process The foamed resin composition obtained in the kneading process is filled into a mold, sealed, and heated under pressure at a temperature above the decomposition temperature of the foaming agent and crosslinking agent for a predetermined time to allow the decomposition of the foaming agent and crosslinking agent to proceed. After that, the mold is opened and the pressure is released to obtain a crosslinked polyolefin foam.

[0071] <Two-stage block foaming method> The two-stage block foaming method comprises, for example, the following steps (1)-(3). (1) Mixing process A foamable resin composition is prepared by melting and kneading polyolefin resin, wood filler, foaming agent, crosslinking agent, and as needed foaming aids, lubricants, and other optional components at a temperature below the decomposition temperature of the foaming agent using a kneading device such as an extruder, Banbury mixer, kneader, or roll. (2) Primary foaming process The foamed resin composition obtained in the kneading process is filled into the molding space of the primary mold and heated under pressure. This decomposes some of the foaming agent and some or all of the crosslinking agent. The pressure is then released, and the foamed resin composition intermediate (primary foam) is removed. The heating temperature is usually determined to be in the range of 120-150°C, and the heating time is usually determined to be in the range of 25-70 minutes. (3) Secondary foaming process The foamable resin composition intermediate (primary foam) obtained in the primary foaming process is placed in the molding space of an unsealed secondary mold, heated under atmospheric pressure to induce secondary foaming, and then cooled before being removed from the secondary mold. The heating temperature is usually determined to be between 140-180°C, and the heating time is usually determined to be between 25 minutes and 6 hours.

[0072] <Three-stage block foaming method> The three-stage block foaming method comprises, for example, the following steps (1)-(4). (1) Mixing process A foamable resin composition is prepared by melting and kneading polyolefin resin, wood filler, foaming agent, crosslinking agent, and as needed foaming aids, lubricants, and other optional components at a temperature below the decomposition temperature of the foaming agent using a kneading device such as an extruder, Banbury mixer, kneader, or roll. (2) Primary foaming process The foamed resin composition obtained in the kneading process is filled into the molding space of the primary mold and heated under pressure. This decomposes some of the foaming agent and some or all of the crosslinking agent. The pressure is then released, and the foamed resin composition intermediate (primary foam) is removed. The heating temperature is usually determined to be in the range of 120-150°C, and the heating time is usually determined to be in the range of 25-70 minutes. (3) Secondary foaming process The foamed resin composition intermediate (primary foam) obtained in the primary foaming process is filled into the molding space of the secondary mold and heated under pressure. This decomposes some of the foaming agent and some or all of the crosslinking agent. The pressure is then released and the foamed resin composition intermediate (secondary foam) is removed. The heating temperature is usually determined to be in the range of 120-150°C, and the heating time is usually determined to be in the range of 25-70 minutes. (4) Tertiary foaming process The foamable resin composition intermediate (secondary foam) obtained in the secondary foaming process is placed in the molding space of an unsealed tertiary mold, heated under atmospheric pressure to induce tertiary foaming, and then the resin foam is removed from the tertiary mold. Alternatively, the foamable resin composition intermediate (secondary foam) obtained in the secondary foaming process is placed in an oven (constant temperature bath) and exposed to low-temperature (approximately 90°C) hot air for about 24 hours to obtain the resin foam.

[0073] <Long-length foaming method using chemical crosslinking> The long foaming method comprises, for example, the following steps (1)-(2). (1) Mixing process Polyolefin resin, wood filler, foaming agent, crosslinking agent, and as needed foaming aids, lubricants, and other optional components are kneaded and extruded into a sheet using a single-screw extruder, twin-screw extruder, etc., to extrude a foamed resin composition (hereinafter referred to as a base sheet) in a predetermined shape such as a sheet. The kneading and extrusion can be performed simultaneously using an extruder. (2) Foaming process The base material obtained in the kneading process is transported into a heating device such as an oven and heated at 120-250°C (above the decomposition temperature of the foaming agent and crosslinking agent) for 5-20 minutes to produce a foamed resin material. It is preferable to use a device in which the heating device such as an oven and the transport device are integrated, as this allows for continuous processing of the base material.

[0074] <Long foaming method using electron beam crosslinking> The long foaming method using electron beam crosslinking comprises, for example, the following steps (1)-(3). (1) Mixing process Polyolefin resin, wood filler, foaming agent, crosslinking agent, and as needed foaming aids, lubricants, and other optional components are kneaded using a single-screw extruder, twin-screw extruder, etc., and a resin composition in a predetermined shape such as a sheet (hereinafter referred to as a base plate) is extruded. Kneading and extrusion can be performed simultaneously using an extruder. (2) Crosslinking process The base plate obtained in the kneading process is crosslinked. The crosslinking method can involve irradiation with ionizing radiation such as electron beams or gamma rays, with electron beam irradiation (electron beam crosslinking) being preferred. Electron beam crosslinking can be performed using an electron beam irradiator. If necessary, crosslinking agents such as the aforementioned organic peroxides may be used in combination. (3) Foaming process The crosslinked base plate obtained in the crosslinking process is transported into a heating device such as an oven and heated at 120-250°C (above the decomposition temperature of the foaming agent) for 5-20 minutes to produce a foamed resin. It is preferable to use a device in which the heating device such as an oven and the transport device are integrated, as this allows for continuous processing of the base plate.

[0075] In the method for producing crosslinked polyolefin foam according to this technology described above, other steps can be performed depending on the purpose. For example, cooling steps, maturation steps, etc., can be performed after the crosslinking and foaming steps. It is also possible to perform molding steps such as trimming the edges or slicing the manufactured foam.

[0076] Furthermore, a bubble-breaking process can be performed to open up (connect) the bubbles in the manufactured foam. The bubble-breaking process involves compressing the resin foam by passing it between two rolls rotating in opposite directions, thereby bursting the closed bubbles (cells) in the cross-linked polyolefin foam and opening up (connecting) the closed bubbles. Here, the compression conditions (compression ratio, roll peripheral speed ratio) during each compression process can be appropriately set according to the degree of open-bubble formation.

[0077] 4. Applications of cross-linked polyolefin foams The cross-linked polyolefin foam according to this technology can be used in a wide range of applications in a wide range of fields due to its high quality. For example, it can be suitably used as cushioning material for furniture, sealing material for furniture, cushioning material for buildings, sealing material for buildings, sealing material for home appliances, packaging material, transport containers, cushioning material for vehicles, interior building materials, interior vehicle materials, cushioning material for home appliances, pipe insulation material, various covers, cushioning materials, toys, general merchandise, cleaners, various sponges, toys, kickboards, floats, sports goods, etc. Because the cross-linked polyolefin foam according to this technology has an ammonia reduction effect and a VOC reduction effect, it can be particularly suitably used as sealing material for furniture, general merchandise, slippers, toilet mats, air conditioner sealing material, etc.

[0078] 5. Odor-reducing agent The odor reducing agent according to this technology is an odor reducing agent for the cross-linked polyolefin foam described above, and is characterized by containing a wood filler. That is, the wood filler described above can be distributed as an odor reducing agent for the cross-linked polyolefin foam according to this technology having the characteristics described above. The cross-linked polyolefin foam to which the odor reducing agent according to this technology is intended is as described above, so its explanation is omitted here. Furthermore, the wood filler, which is the active ingredient of the odor reducing agent according to this technology, is the same as the wood filler that can be used with the cross-linked polyolefin foam according to this technology described above, so its explanation is omitted here.

[0079] Other components may be used in combination with the odor reducing agent related to this technology, as long as they do not impair the action or effect of this technology. Other components may include, for example, excipients, disintegrants, lubricants, stabilizers, pH adjusters, colorants, and other components commonly used in formulation. Furthermore, one or more components that can be used in the aforementioned cross-linked polyolefin foam may be included in the odor reducing agent. In addition, known or future-discovered functional components may be used in combination as appropriate for the purpose.

[0080] This technology can take the following forms: [1] A crosslinked polyolefin foam obtained by crosslinking a polyolefin resin, Contains wood filler, Density is 60 kg / m³ 3 The following is a cross-linked polyolefin foam. [2] A cross-linked polyolefin foam as described in [1], using petroleum resin as a raw material. [3] The aforementioned petroleum resin is a C9-type petroleum resin, as described in [2], a cross-linked polyolefin foam. [4] The aforementioned petroleum resin is a hydrogenated petroleum resin, the crosslinked polyolefin foam according to [2] or [3]. [5] A cross-linked polyolefin foam according to any one of [1] to [4], containing an inorganic filler. [6] An odor reducing agent for crosslinked polyolefin foam obtained by crosslinking polyolefin resins, Contains wood filler, Density is 60 kg / m³ 3 Odor reducers for the following cross-linked polyolefin foams. [7] The odor reducing agent according to [6], wherein the raw material for the cross-linked polyolefin foam is petroleum resin. [8] The odor reducing agent described in [7], wherein the petroleum resin is a C9-type petroleum resin. [9] The odor reducing agent according to [7] or [8], wherein the petroleum resin is a hydrogenated petroleum resin.

[10] The odor reducing agent according to any one of [6] to [9], wherein the crosslinked polyolefin foam contains an inorganic filler. [Examples]

[0081] The present technology will be described in more detail below based on the following examples. The examples described below are representative examples of the present technology and should not be interpreted as narrowing the scope of the present technology.

[0082] <Experimental Example 1> Experimental Example 1 investigated the differences in physical properties of cross-linked polyolefin foam when wood fillers are used with the foam.

[0083] 1.Raw materials • Olefin resin: Ethylene-vinyl acetate copolymer (EVA), "UltraSen 630" manufactured by Tosoh Corporation • Petroleum resin masterbatch: C9 series hydrogenated petroleum resin (partially hydrogenated), "Alcon M-90" manufactured by Arakawa Chemical Industries, Ltd. • Foaming agent masterbatch: Azodicarbonamide (ADCA), manufactured by Eiwa Kasei Kogyo Co., Ltd. • Inorganic filler: Calcium carbonate, "Snowlight SSS" manufactured by Maruo Calcium Co., Ltd. • Crosslinking agent: Dicumyl peroxide (DCP), "PERKADOX BC-FF" manufactured by Kayaku Akzo Co., Ltd. • Foaming agent 1: Urea, manufactured by Eiwa Chemical Industries Co., Ltd. "Cell Paste 101" • Foaming agent 2: Zinc stearate, manufactured by Tannan Chemical Industry Co., Ltd. "Zinc Stearate (Tannan)" • Dispersant: Polyethylene-based wax, "Sunwax 131-P" manufactured by Sanyo Chemical Industries, Ltd. • Wood filler: Fibrous components of fir branches and leaves manufactured as described below, manufactured by Nippon Kaori Research Institute Co., Ltd., average particle size 7 μm and 1 mm (Manufacturing method) Approximately 50 kg of fir branches and leaves, crushed to an average length of 30 mm and a thickness of 5 mm using a crushing-type pulverizer (manufactured by KYB Manufacturing Co., Ltd.), was placed in the distillation tank of a microwave distillation apparatus. While stirring, the pressure in the distillation tank was maintained under reduced pressure conditions of approximately 20 kPa (steam temperature approximately 67°C), and distillation was carried out by microwave irradiation for 1 hour. After distillation, 20 kg of extraction residue was obtained after the oil content of the fir leaves had been extracted. The distillate was recovered from the distillate extraction tube connected to the distillation tank. Subsequently, the extraction residue was placed in a drying pulverizer, dried and pulverized at 60°C for 2 hours, and then sieved to obtain 5 kg of powder with an average particle size of approximately 1 mm. Furthermore, 1 kg of this powder was placed in a precision pulverizer to obtain powder with an average particle size of approximately 7 μm.

[0084] 2. Manufacturing of cross-linked polyolefin foam (1) Mixing process The raw material mixture was kneaded using a kneader at 100-130°C for 15-20 minutes according to the proportions listed in Table 1 below. The resulting raw material mixture was further kneaded using a 10-inch mixing roll at 100°C for 10-15 minutes. (2) Primary foaming process The mixed raw material composition was filled into the molding space (175 mm × 175 mm × t28 mm) of the primary mold. It was heated under pressure at 133°C for 68 minutes, and the primary foam was removed from the mold. (3) Secondary foaming process The primary foam was filled into the molding space (500mm x 500mm x t100mm) of the secondary mold. It was heated at 167°C for 2 hours and 20 minutes under atmospheric pressure, and the secondary foam was removed from the mold. (4) Foam breaking process A resin foam was passed between two rolls rotating in opposite directions to obtain an open-cell cross-linked polyolefin foam.

[0085] 3. Evaluation The physical properties of the manufactured cross-linked polyolefin foam were evaluated using the following method.

[0086] [density] The density of the cross-linked polyolefin foam was measured in accordance with JIS K6767.

[0087] [50% compressive stress] The 50% compressive stress of the cross-linked polyolefin foam was measured at a compression rate of 10 mm / min in accordance with JIS K6767.

[0088] [Compression permanent strain] The compression set of the cross-linked polyolefin foam was measured in accordance with JIS K6767 under conditions of 25% compression, 22 hours, and 23°C.

[0089] [Odor component reduction effect] The deodorizing performance of cross-linked polyolefin foam was evaluated based on the amount of ammonia absorbed. A 10L Tedlar bag was filled with gas at a predetermined concentration, and the cross-linked polyolefin foam was placed inside and allowed to stand. The gas concentration was then evaluated using a detector tube. Samples were cut from the cross-linked polyolefin foam into 20cm x 20cm x 1cm pieces. The initial gas concentration was 30ppm or 17ppm. Deodorizing performance was confirmed by the change in ammonia concentration over time.

[0090] 4.Results The results are shown in Table 1 below. [Table 1]

[0091] 5. Discussion As shown in Table 1, Examples 1 to 5, which contained wood filler, showed superior effectiveness in reducing ammonia, an odor component, compared to Comparative Example 1, which did not contain wood filler.

[0092] Comparing the examples, it was confirmed that adding a wood filler with a smaller average particle size resulted in improved compression set.

Claims

1. A crosslinked polyolefin foam obtained by crosslinking a polyolefin resin, Contains wood filler, Density of 60 kg / m³ ３ The following is a cross-linked polyolefin foam.

2. A crosslinked polyolefin foam according to claim 1, wherein petroleum resin is used as a raw material.

3. The crosslinked polyolefin foam according to claim 2, wherein the petroleum resin is a C9-type petroleum resin.

4. The crosslinked polyolefin foam according to claim 2, wherein the petroleum resin is a hydrogenated petroleum resin.

5. A crosslinked polyolefin foam according to claim 1, comprising an inorganic filler.

6. An odor reducing agent for crosslinked polyolefin foam obtained by crosslinking polyolefin resins, Contains wood filler, Density of 60 kg / m³ ３ Odor reducers for the following cross-linked polyolefin foams.

7. The odor reducing agent according to claim 6, wherein the raw material for the cross-linked polyolefin foam is petroleum resin.

8. The odor reducing agent according to claim 7, wherein the petroleum resin is a C9-type petroleum resin.

9. The odor reducing agent according to claim 7, wherein the petroleum resin is a hydrogenated petroleum resin.

10. The odor reducing agent according to claim 6, wherein the cross-linked polyolefin foam contains an inorganic filler.

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