Composition containing polymer and zinc-containing hydrotalcite

Abstract

To provide a composition from which a molding or a vulcanized molding having excellent water resistance can be obtained.SOLUTION: In a composition containing a polymer and a hydrotalcite according to the present invention, the hydrotalcite is represented by a following chemical formula (1) and has a first peak whose 2θ starts from 28-32° and ends at 38-41°, a second peak whose 2θ starts from 38-41°and ends at 45-47°, and a third peak whose 2θ starts from 59-61° and ends at 64-66°in a powder X-ray diffraction pattern. The hydrotalcite is contained in an amount of 1-12 pts.mass based on 100 pts.mass of the polymer. M2+xZnyM3+zOx+y+(3 / 2)z (1) (where M2+ represents at least one kind of a divalent metal ion; M3+ represents at least one kind of a trivalent metal ion; and x, y and z represent numbers satisfying 0<x≤0.5, 0<y≤0.2 and 0<z≤0.4, respectively).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composition comprising a polymer such as chloroprene rubber or vinyl chloride resin, and a specific zinc-containing hydrotalcite. [Background technology]

[0002] Generally, polymers used in various industrial applications possess properties (such as mechanical properties and flame retardancy) suited to their respective uses. For example, chloroprene rubber and polyvinyl chloride resin excel in properties such as flame retardancy, and these properties are utilized in a wide range of fields, including automotive parts and various industrial components.

[0003] In compositions containing such polymers, there is a need to further improve the various properties of the polymer, and in some cases, excellent water resistance may be required depending on the usage environment. For example, Patent Document 1 discloses a chloroprene rubber composition mainly composed of chloroprene rubber and containing a calcined hydrotalcite product as a metal oxide vulcanizing agent. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-012392 [Overview of the project] [Problems that the invention aims to solve]

[0005] Although the chloroprene rubber composition disclosed in Patent Document 1 is said to have excellent water resistance and is less prone to defects such as foaming, voids, and blistering in molded products during vulcanization, sufficient water resistance may still not be obtained depending on the usage environment, and further improvements are needed.

[0006] In addition, since the chloroprene rubber composition disclosed in Patent Document 1 is limited to those containing chloroprene rubber as a polymer, there is a risk that the same effects cannot be obtained in compositions containing other polymers that require water resistance.

[0007] Therefore, an object of the present invention is to provide a composition capable of obtaining a molded body or a vulcanized molded body having excellent water resistance.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above object, the inventors have found that by strongly calcining hydrotalcite containing zinc (Zn) as an essential component under specific temperature conditions of 400°C to 850°C, a hydrotalcite having a unique powder X-ray diffraction pattern not found in conventional hydrotalcite can be obtained. Furthermore, it has been found that a composition obtained by incorporating this hydrotalcite into a polymer such as chloroprene rubber or vinyl chloride resin can obtain a molded body or a vulcanized molded body having excellent water resistance. The present invention has been completed based on such findings and includes the aspects of the following items.

[0009] (Item 1) A composition containing a polymer and hydrotalcite, where the hydrotalcite is represented by the following chemical formula (1) and has a first peak, a second peak, and a third peak in the powder X-ray diffraction pattern, the 2θ of the first peak starts from 28° to 32° and ends at 38° to 41°, the 2θ of the second peak starts from 38° to 41° and ends at 45° to 47°, the 2θ of the third peak starts from 59° to 61° and ends at 64° to 66°, and the composition contains 1 to 12 parts by mass of the hydrotalcite with respect to 100 parts by mass of the polymer. M M 2+ x Zn y ·M 3+z O x+y+(3 / 2)z (1) (wherein M 2+ represents at least one divalent metal ion, M 3+ represents at least one trivalent metal ion, and x, y, and z each represent a number satisfying 0 < x ≦ 0.5, 0 < y ≦ 0.2, and 0 < z ≦ 0.4.)

[0010] (Item 2) The composition according to Item 1, wherein the polymer contains a halogen-based polymer.

[0011] (Item 3) The composition according to Item 2, wherein the halogen-based polymer contains at least one halogen-based polymer selected from chloroprene rubber, chloroprene rubber containing acrylonitrile monomer units, chlorinated butyl rubber, brominated butyl rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, and fluororubber.

[0012] (Item 4) The composition according to Item 2, wherein the halogen-based polymer contains a vinyl chloride-based resin.

[0013] (Item 5) The composition according to Item 1, wherein the polymer contains a non-halogen-based polymer.

[0014] (Item 6) The composition according to Item 5, wherein the non-halogen-based polymer contains at least one non-halogen-based polymer selected from ethylene propylene diene rubber, styrene butadiene rubber, natural rubber, isoprene rubber, silicone rubber, butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, and acrylic rubber.

[0015] (Item 7) The composition according to any one of Items 1 to 6, wherein the specific surface area of the hydrotalcite is 120 m 2 / g to 250 m 2 / g.

[0016] (Item 8) In the hydrotalcite, in the chemical formula (1), M2+ is Mg 2+ and M 3+ is Al 3+ The composition according to any one of items 1 to 7, characterized in that

[0017] (Item 9) A vulcanizate of the composition according to item 3 or 6.

[0018] (Item 10) A vulcanized molded article using the vulcanizate according to item 9.

[0019] (Item 11) A method of incorporating hydrotalcite into a polymer, where the hydrotalcite is represented by the following chemical formula (1) and has a first peak, a second peak, and a third peak in the powder X-ray diffraction pattern, the 2θ of the first peak starts from 28° to 32° and ends at 38° to 41°, the 2θ of the second peak starts from 38° to 41° and ends at 45° to 47°, the 2θ of the third peak starts from 59° to 61° and ends at 64° to 66°, and the method is characterized in that 1 to 12 parts by mass of the hydrotalcite is contained with respect to 100 parts by mass of the polymer. M 2+ x Zn y ·M 3+ z O x+y+(3 / 2)z (1) (In the formula, M 2+ represents at least one divalent metal ion, M 3+ represents at least one trivalent metal ion, and x, y, and z each represent a number satisfying 0 < x ≤ 0.5, 0 < y ≤ 0.2, and 0 < z ≤ 0.4.)

Advantages of the Invention

[0020] According to the composition of the present invention, a molded article or a vulcanized molded article having excellent water resistance can be obtained.

Brief Description of the Drawings

[0021] [Figure 1] Figure 1 is a graph showing the powder X-ray diffraction patterns of hydrotalcites A to E used in each example and comparative example.

Embodiments of the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited only to the embodiments described below.

[0023] [Composition] One embodiment of the present invention is a composition containing a polymer and a hydrotalcite, wherein the hydrotalcite is represented by the following chemical formula (1), and in the powder X-ray diffraction pattern, it has a first peak, a second peak, and a third peak. The 2θ of the first peak starts from 28° to 32° and ends at 38° to 41°, the 2θ of the second peak starts from 38° to 41° and ends at 45° to 47°, and the 2θ of the third peak starts from 59° to 61° and ends at 64° to 66° (hereinafter, such a powder X-ray diffraction pattern may be simply referred to as a "specific powder X-ray diffraction pattern"). Further, the composition contains 1 to 12 parts by mass of hydrotalcite with respect to 100 parts by mass of the polymer. M 2+ x Zn y ·M 3+ z O x+y+(3 / 2)z (1) (In the formula, M 2+ represents at least one divalent metal ion, M 3+ represents at least one trivalent metal ion, and x, y, and z represent numbers satisfying 0 < x ≤ 0.5, 0 < y ≤ 0.2, and 0 < z ≤ 0.4, respectively.)

[0024] Hydrotalcite represented by the above chemical formula (1) and having a unique powder X-ray diffraction pattern can be obtained by strongly firing hydrotalcite containing Zn as an essential component under specific temperature conditions of 400°C to 850°C. Compositions obtained by incorporating this specific zinc-containing hydrotalcite into polymers such as chloroprene rubber or vinyl chloride resin can exhibit excellent water resistance when processed into molded or vulcanized articles.

[0025] The mechanism by which the composition of this embodiment improves the water resistance of molded articles and vulcanized articles is not clear, and is not bound by any theory, but it can be considered as follows.

[0026] First, uncalcined zinc-containing hydrotalcite consists of a base layer formed by magnesium (Mg), aluminum (Al), and zinc (Zn) hydroxides, and interlayer water and carbonate ions (CO3) present between the two base layers. 2- It has a layered structure comprising an intermediate layer formed by ) and . When this uncalcined zinc-containing hydrotalcite is strongly calcined under specific temperature conditions of 400°C to 850°C, the interlayer water and carbonate ions in the intermediate layer are released, and the hydroxide in the base layer changes into oxides, namely aluminum oxide (Al2O3), magnesium oxide (MgO), and zinc oxide (ZnO). At this time, the oxides that have changed from the hydroxide in the base layer remain while maintaining the layered structure. Zinc-containing hydrotalcite that has been strongly calcined in this way has its specific surface area greatly increased by the release of water present in the base layer and interlayers, so the portion that can react with acids increases, making it easier for neutralization reactions with acids to occur (i.e., it has high acid-receiving capacity) and exhibiting excellent thermal stability.

[0027] Furthermore, in a composition containing such strongly calcined zinc-containing hydrotalcite in a halogen-based polymer (e.g., chloroprene rubber or vinyl chloride resin), the strongly calcined zinc-containing hydrotalcite in the composition reacts with acid, changing the oxide of the base layer into salts (e.g., aluminum chloride (AlCl3), magnesium chloride (MgCl2), and zinc chloride (ZnCl2)). Therefore, when water comes into contact with a molded or vulcanized molded body formed from the above composition, the base layer and intermediate layer of the hydrotalcite draw in water and salts, causing the salts in the base layer to change back into hydroxides, as well as the water (interlayer water) and acid anions (i.e., chloride ions (Cl2)). - As a result, the intermediate layer is retained, and the hydrotalcite is thought to transform into zinc-containing hydrotalcite with a layered structure comprising a base layer formed by hydroxide and an intermediate layer containing interlayer water, etc. Due to the action of this strongly calcined zinc-containing hydrotalcite, even if water comes into contact with a molded or vulcanized molded body formed by the above composition, the zinc-containing hydrotalcite transforms as described above, thereby reducing the effect of water on the polymer and resulting in excellent water resistance.

[0028] Furthermore, as mentioned above, strongly calcined zinc-containing hydrotalcite has a significantly increased specific surface area due to the calcination process. Therefore, when incorporated into polymers such as chloroprene rubber, the ZnO in the base layer can act as a highly active metal oxide (for example, a metal oxide-based vulcanizing agent), which offers the advantage of reducing the amount added compared to conventional, less active zinc oxide.

[0029] On the other hand, in a composition containing strongly calcined zinc-containing hydrotalcite in a non-halogenated polymer (e.g., ethylene propylene diene rubber), the strongly calcined zinc-containing hydrotalcite in the composition has a significantly increased specific surface area, as described above. Because it acts as a vulcanizing agent with highly active ZnO on its surface, it is more reactive than when using conventional metal oxide vulcanizing agents such as ZnO, which have low activity. This increases the vulcanization density of the vulcanized product formed by the above composition, meaning that a denser three-dimensional network structure can be formed in the vulcanized product. Therefore, even if water comes into contact with the vulcanized product, water molecules are less likely to physically penetrate the three-dimensional network structure of the vulcanized product, resulting in excellent water resistance.

[0030] In this specification, the "beginning" and "end" of a peak in a powder X-ray diffraction pattern are defined as follows, depending on the morphology of the peak: If two peaks overlap, the minimum point of the overlapping portion is defined as the beginning of one peak and the end of the other peak. For example, in the powder X-ray diffraction pattern of hydrotalcite A (HT-A) shown in Figure 1, the end of the first peak (P1) and the beginning of the second peak (P2) are defined as the minimum point of the overlapping portion of the first and second peaks. If a particular peak does not overlap with other peaks, the rising portion of the peak relative to the baseline of the powder X-ray diffraction pattern is defined as the beginning and end of the peak.

[0031] The various components of the composition are described below.

[0032] [polymer] The polymer is not particularly limited, and any polymer can be used depending on the application. Examples of such polymers include halogenated polymers such as chloroprene rubber and vinyl chloride resins; and non-halogenated polymers such as ethylene propylene diene rubber. These polymers can be used individually or in combination of two or more polymers.

[0033] (Halogenated polymer) Halogen-based polymers are not particularly limited, but examples include rubbers and resins containing halogens.

[0034] Specific examples of rubber containing halogens include chlorine-based rubbers such as chloroprene rubber, chloroprene rubber containing acrylonitrile monomer units, chlorinated butyl rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, and epichlorohydrin rubber; brominated rubbers such as brominated butyl rubber; and fluorine-based rubbers such as fluororubber.

[0035] Specific examples of halogen-containing resins include polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylitene, chlorinated polyethylene, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene copolymer, vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-maleic acid ester copolymer, vinyl chloride-methacrylate ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-various vinyl ether copolymers, and other vinyl chloride-based resins.

[0036] These halogenated polymers can be used in combination with other halogen-free polymers (i.e., non-halogenated polymers), such as acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, ethylene-vinyl acetate copolymers, ethylene-ethyl (meth)acrylate copolymers, polyesters, etc. Halogenated polymers and non-halogenated polymers can be used, for example, in the form of mixtures of halogenated polymers and non-halogenated polymers, block copolymers, or graft copolymers.

[0037] In one embodiment, the polymer is preferably a halogenated polymer, more preferably a halogenated rubber from the viewpoint of water resistance, and even more preferably a rubber that includes at least one selected from chloroprene rubber, chloroprene rubber containing acrylonitrile monomer units, chlorinated butyl rubber, brominated butyl rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, and fluororubber, and particularly preferably a rubber that includes at least one of chloroprene rubber and chloroprene rubber containing acrylonitrile monomer units.

[0038] In another embodiment, the polymer is preferably a halogenated polymer containing a vinyl chloride resin. While vinyl chloride resins are inherently prone to problems such as foaming and reduced thermal stability in molded articles, the inclusion of the aforementioned strongly calcined zinc-containing hydrotalcite in the composition suppresses these problems while exhibiting excellent water resistance.

[0039] (Non-halogen polymers) Non-halogen polymers are not particularly limited, but examples include halogen-free rubber and resins.

[0040] Specific examples of halogen-free rubber include ethylene propylene diene rubber (EPDM), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), natural rubber, isoprene rubber, silicone rubber, butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, and acrylic rubber.

[0041] Specific examples of halogen-free resins include thermoplastic resins such as olefin resins (e.g., polyethylene, copolymers of ethylene and other α-olefins, polypropylene, copolymers of propylene and other α-olefins, polybutene-1, poly-4-methylpentene-1, etc.), polystyrene, copolymers of styrene and acrylonitrile, polyvinyl acetate, polylactic acid, polyvinyl alcohol, polyacrylate, polymethacrylate, polyurethane, polyester, polyether, polyamide, ABS, polycarbonate, and polyphenylene sulfide; and thermosetting resins such as phenolic resins, melamine resins, epoxy resins, unsaturated polyester resins, and alkyd resins.

[0042] In one embodiment, the polymer is preferably a non-halogenated polymer, more preferably a halogen-free rubber from the viewpoint of water resistance, and even more preferably a polymer containing at least one rubber selected from ethylene propylene diene rubber, styrene butadiene rubber, natural rubber, isoprene rubber, silicone rubber, butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, and acrylic rubber.

[0043] [Hydrotalcite] Hydrotalcite is obtained by strongly calcining uncalcined zinc-containing hydrotalcite under specific temperature conditions of 400°C to 850°C, and is represented by the following chemical formula (1), and has a powder X-ray diffraction pattern that includes a first peak where 2θ starts from 28° to 32° and ends at 38° to 41°, a second peak where 2θ starts from 38° to 41° and ends at 45° to 47°, and a third peak where 2θ starts from 59° to 61° and ends at 64° to 66°. M 2+ x Zn y ·M 3+ z O x+y+(3 / 2)z (1) (In the formula, M 2+ represents at least one divalent metal ion, M 3+represents at least one trivalent metal ion, and x, y, and z represent numbers satisfying 0 < x ≤ 0.5, 0 < y ≤ 0.2, and 0 < z ≤ 0.4, respectively.)

[0044] As described above, such hydrotalcite can not only improve water resistance but also act as a heat stabilizer, an acid acceptor, and a vulcanizing agent. Further, since the interlayer water and carbonate ions (interlayer anions) present between the layers of the layered structure of the hydrotalcite before calcination are removed by strong calcination, even when the composition is processed into a molded body, a vulcanized molded body, etc., foaming due to interlayer water and carbonate ions is less likely to occur.

[0045] In addition, the above-mentioned strongly calcined zinc-containing hydrotalcite has zinc oxide (ZnO) formed on the surface by strong calcination. Since the amount of water generated by the neutralization reaction of ZnO is less than that of MgO, etc., there is an advantage that foaming and deterioration of thermal stability are less likely to occur.

[0046] M in the above chemical formula (1) of hydrotalcite 2+ and M 3+ The types of metals are not particularly limited, and any metal that can be contained in hydrotalcite can be adopted. In one embodiment, M 2+ in the above chemical formula (1) is magnesium ion (Mg 2+ ), and M 3+ is preferably aluminum ion (Al 3+ ). When the hydrotalcite has such a specific composition, excellent water resistance can be more reliably obtained, and foaming and deterioration of thermal stability described above can be made less likely to occur.

[0047] As described above, when the basic layer hydroxide of the strongly calcined zinc-containing hydrotalcite changes to an oxide by strong calcination, the water present in the basic layer and the interlayer of the layered structure is released, so the specific surface area is greatly increased. However, the specific surface area of such hydrotalcite is 120 m 2 / g to 250 m 2It is preferable that it be / g, 150m 2 / g~200m 2 It is more preferable that the specific surface area is within this specific range. When the specific surface area is within this range, the water resistance of molded or vulcanized molded articles can be more reliably improved, and problems such as foaming and decreased thermal stability can be less likely to occur.

[0048] Furthermore, hydrotalcite with such a specific surface area can be obtained by strongly calcining uncalcined zinc-containing hydrotalcite under temperature conditions within the range of 400°C to 850°C, as described above.

[0049] The hydrotalcite content is 1 to 12 parts by mass per 100 parts by mass of polymer. Having a hydrotalcite content within this specific range can more reliably improve the water resistance of molded or vulcanized articles.

[0050] Zinc-containing hydrotalcite represented by the above chemical formula (1) and having the above-described characteristic powder X-ray diffraction pattern can be obtained, as described above, by strongly calcining uncalcined zinc-containing hydrotalcite under specific temperature conditions of 400°C to 850°C. Note that calcining uncalcined zinc-containing hydrotalcite at temperatures below 400°C makes it difficult to obtain oxides with high acid reactivity, while calcining at temperatures above 850°C makes it difficult to maintain the layered structure of hydrotalcite, resulting in a spinel-type structure and consequently a decrease in thermal stability. The preferred calcination temperature range is 450°C to 800°C.

[0051] The calcination time for strongly calcining uncalcined zinc-containing hydrotalcite is not particularly limited, but it should be sufficient to calcine it to a degree in which oxide peaks can be confirmed by powder X-ray diffraction (XRD). Such a calcination time depends on the calcination temperature, but for example, it can be 30 minutes or more, preferably 1 hour or more, and more preferably 2 hours or more.

[0052] (Surface treatment) Hydrotalcite may be surface-treated to improve its dispersibility in the composition. While not particularly limited, the surface treatment agents that can be used for this treatment include, for example, anionic surfactants, cationic surfactants, phosphate ester treatment agents, silane coupling agents, titanate coupling agents, aluminum coupling agents, silicone treatment agents, silicic acid, and water glass. Particularly preferred surface treatment agents include at least one selected from the group consisting of oleic acid, stearic acid, octanoic acid, and octicic acid. The amount of the surface treatment agent is not particularly limited, but is, for example, 0.01 to 20% by mass, preferably 0.1 to 15% by mass, relative to the mass of the hydrotalcite.

[0053] [Other additives] In one embodiment, the composition may contain other additives besides hydrotalcite, as long as they do not impede the effects of the present invention. Such other additives are not particularly limited, but include, for example, fillers and reinforcing materials (e.g., carbon black, silica, clay, talc, calcium carbonate, etc.), plasticizers (e.g., phthalate-based plasticizers such as diisononyl phthalate, ester-based plasticizers, vegetable oils, etc.), vulcanizing agents (e.g., metal oxides such as zinc oxide), vulcanization accelerators (e.g., trimethylthiourea compounds, etc.), processing aids and lubricants (e.g., fatty acids such as stearic acid, paraffin-based processing aids, fatty acid amides, etc.), anti-aging agents (e.g., ozone-resistant anti-aging agents such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, heat-resistant anti-aging agents such as 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, octylated diphenylamine, etc.), and acid acceptors (e.g., metal oxides such as magnesium oxide and zinc oxide). These additives may be used individually or in combination of two or more.

[0054] [Method for producing the composition] A composition according to one embodiment of the present invention can be obtained by incorporating zinc-containing hydrotalcite represented by the above chemical formula (1) and having the above characteristic powder X-ray diffraction pattern into a polymer. In this case, any other additives may be incorporated into the polymer in addition to hydrotalcite.

[0055] When incorporating the hydrotalcite described above into a polymer, the polymer and the hydrotalcite can be mixed or kneaded using any mixing or kneading means. The mixing or kneading means are not particularly limited and include, for example, a Banbury mixer, a kneader mixer, a single-screw or twin-screw extruder, a double-roll extruder, and so on.

[0056] [Molded body] In one embodiment of the present invention, a desired molded article can be obtained by any molding means using a composition containing a polymer and the hydrotalcite described above. The molding means used to manufacture the molded article is not particularly limited, and any molding means can be used depending on the type of polymer and the intended use of the molded article. Examples of such molding means include injection molding, extrusion molding, blow molding, press molding, rotational molding, calendering, sheet forming, transfer molding, lamination molding, and vacuum forming.

[0057] Molded articles formed from the polymer and the aforementioned hydrotalcite composition exhibit excellent water resistance and are less prone to molding defects such as foaming, making them suitable for use as various resin products with excellent water resistance and mechanical properties.

[0058] In this specification, an unvulcanized molded article (for example, a molded article made using a polymer other than rubber) is simply referred to as a molded article, and a vulcanized molded article is referred to as a vulcanized molded article.

[0059] [Vulcanized products and vulcanized molded articles] In another embodiment of the present invention, a vulcanized product can be produced by vulcanizing a composition (i.e., a rubber composition) containing rubber such as chloroprene rubber and the above-mentioned hydrotalcite. In yet another embodiment of the present invention, a vulcanized molded article can be produced by molding using the above-mentioned vulcanized product. The vulcanized molded article may be formed into a predetermined shape after vulcanizing the rubber composition, or it may be vulcanized after forming the rubber composition into a predetermined shape. The molding means used to produce the vulcanized molded article is not particularly limited and examples include press molding, extrusion molding, and calendering.

[0060] Vulcanized products or molded articles formed from the rubber composition containing the aforementioned rubber and hydrotalcite exhibit excellent water resistance and are less prone to molding defects such as foaming. Therefore, they can be suitably used as various rubber products (e.g., belts, hoses, coverings, etc.) with excellent water resistance and mechanical properties.

[0061] The present invention is not limited to the embodiments described above or the examples described later, and can be appropriately combined, substituted, or modified without departing from the purpose and spirit of the present invention. In this specification, ordinal numbers such as "1st," "2nd," etc., are used to distinguish the items to which they are assigned, and do not indicate the order, priority, importance, etc. of each item. [Examples]

[0062] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0063] (Example 1) <Preparation of chloroprene rubber composition> 100 parts by mass of chloroprene rubber (manufactured by Denka Co., Ltd., mercaptan-modified chloroprene rubber, Mooney viscosity ML1+4 (100℃) = 48) as a polymer component, and hydrotalcite B (manufactured by Kyowa Chemical Industry Co., Ltd., raw material metal species: MgAlZn, BET specific surface area: 194 m²), which is a zinc-containing hydrotalcite that satisfies the above chemical formula (1) and has the above characteristic powder X-ray diffraction pattern. 2 The composition of Example 1 (rubber composition) was prepared by blending 2 parts by mass of (1 / g) with 0.5 parts by mass of stearic acid (manufactured by Shin Nippon Rika Co., Ltd., stearic acid 50S) as a lubricant, 30 parts by mass of SRF carbon black (manufactured by Asahi Carbon Co., Ltd., Asahi #35) as a filler, 1 part by mass of phenyl-1-naphthylamine (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Nocrack PA), a heat-resistant antioxidant, and 1 part by mass of trimethylthiourea (TMU; manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noxellar TMU) as a vulcanization accelerator, and kneading using an 8-inch roll.

[0064] Furthermore, the hydrotalcite used in Example 1 and each of the subsequent examples and comparative examples was analyzed by powder X-ray diffraction, as described later, and its respective powder X-ray diffraction pattern was confirmed.

[0065] (Examples 2-4) The rubber compositions of Examples 2 to 4 were prepared in the same manner as in Example 1, except that the amount of hydrotalcite B was changed to 4 parts by mass, 8 parts by mass, and 12 parts by mass, respectively.

[0066] (Example 5) Instead of hydrotalcite B, hydrotalcite A (manufactured by Kyowa Chemical Industry Co., Ltd., raw material metal species: MgAlZn, BET specific surface area: 155 m²) is a zinc-containing hydrotalcite that satisfies the above chemical formula (1) and has the above-described characteristic powder X-ray diffraction pattern. 2 The rubber composition of Example 5 was prepared in the same manner as in Example 1, except that 8 parts by mass of ( / g) were added.

[0067] (Example 6) The rubber composition of Example 6 was prepared in the same manner as in Example 3, except that 3 parts by mass of zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., zinc oxide type 2) was further added as an acid acceptor.

[0068] (Example 7) The rubber composition of Example 7 was prepared in the same manner as in Example 3, except that chloroprene rubber containing acrylonitrile monomer units (manufactured by Denka Co., Ltd.) was used instead of chloroprene rubber (mercaptan-modified chloroprene rubber).

[0069] (Comparative Examples 1 and 2) The rubber compositions of Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, except that the amount of hydrotalcite B was changed to 0.5 parts by mass and 16 parts by mass, respectively.

[0070] (Comparative Example 3) Instead of hydrotalcite B, hydrotalcite C (manufactured by Kyowa Chemical Industry Co., Ltd., raw material metal species: MgAlZn, BET specific surface area: 10¹ m²) is a zinc-containing hydrotalcite whose powder X-ray diffraction pattern differs from the characteristic diffraction pattern described above. 2 A rubber composition for Comparative Example 3 was prepared in the same manner as in Example 3, except that 8 parts by mass of ( / g) were added.

[0071] (Comparative Example 4) Instead of hydrotalcite B, hydrotalcite D (manufactured by Kyowa Chemical Industry Co., Ltd., raw material metal species: MgAl, BET specific surface area: 131 m²) is a zinc-free hydrotalcite that does not contain zinc (i.e., does not satisfy the above chemical formula (1)) and whose powder X-ray diffraction pattern is different from the characteristic diffraction pattern described above. 2 A rubber composition for Comparative Example 4 was prepared in the same manner as in Example 3, except that 8 parts by mass of ( / g) were added.

[0072] (Comparative Example 5) A rubber composition for Comparative Example 5 was prepared in the same manner as in Example 1, except that instead of hydrotalcite B, 4 parts by mass and 3 parts by mass of magnesium oxide (Kyowa Chemical Industry Co., Ltd., Kyowa Mag 150) and zinc oxide (Sakai Chemical Industry Co., Ltd., Zinc Oxide Type 2) were added, respectively, as acid acceptors.

[0073] <Fabrication and Evaluation of Cumulated Molded Products> The rubber compositions of Examples 1-7 and Comparative Examples 1-5 were each press-vulcanized at 170°C for 20 minutes to produce 2 mm thick vulcanized molded sheets. Furthermore, the water resistance of the vulcanized molded sheets thus produced was evaluated by measuring the volume change rate according to the <Water Resistance Test> described below. The results of the volume change rate measurement in the water resistance test, along with the formulations of the rubber compositions of Examples 1-7 and Comparative Examples 1-5, are shown in Table 1 below.

[0074] <Water resistance test> A test specimen measuring 20 mm in width, 50 mm in length, and 2 mm in thickness was obtained using a sheet-like molded body. The test specimen was immersed in 80°C water for 288 hours, and the volume change rate was measured by measuring the volume of the test specimen before and after immersion. The volume of the test specimen was measured using an electronic hydrometer manufactured by Alpha Mirage Co., Ltd. The volume change rate ΔV is calculated using the following formula: "Volume change rate ΔV (%) = 100 × (W2 - W1) / W1", where W1 is the volume of the test specimen before immersion and W2 is the volume after immersion.

[0075] [Table 1]

[0076] (Example 8) <Preparation of polyvinyl chloride resin composition> The composition of Example 8 (resin composition) was prepared by mixing 100 parts by mass of polyvinyl chloride resin (Shin-Etsu Chemical Co., Ltd., TK-1300) as a polymer component with 1 part by mass of the above-mentioned hydrotalcite B, 50 parts by mass of diisononyl phthalate (DINP; manufactured by Daihachi Chemical Industry Co., Ltd.) as a plasticizer, 30 parts by mass of calcium carbonate (Shiraishi Calcium Co., Ltd., Whiteon SB) as a filler, and 0.1 parts by mass of stearic acid (Shin Nippon Rika Co., Ltd., Stearic Acid 50S) as a lubricant, and kneading the mixture at 170°C for 5 minutes using an 8-inch roll.

[0077] (Examples 9-12) The resin compositions of Examples 9 to 12 were prepared in the same manner as in Example 8, except that the amount of hydrotalcite B was changed to 3 parts by mass, 5 parts by mass, 8 parts by mass, and 12 parts by mass, respectively.

[0078] (Example 13) The resin composition of Example 13 was prepared in the same manner as in Example 8, except that 3 parts by mass of hydrotalcite A were added instead of hydrotalcite B.

[0079] (Example 14) Instead of hydrotalcite B, hydrotalcite E (manufactured by Kyowa Chemical Industry Co., Ltd., raw material metal species: MgAlZn, BET specific surface area: 130 m²) is a zinc-containing hydrotalcite that satisfies the above chemical formula (1) and has the above-described characteristic powder X-ray diffraction pattern. 2 The resin composition of Example 14 was prepared in the same manner as in Example 8, except that 3 parts by mass of ( / g) were added.

[0080] (Comparative Examples 6-8) The resin compositions of Comparative Examples 6 to 8 were prepared in the same manner as in Example 8, except that the amount of hydrotalcite B was changed to 0.5 parts by mass, 16 parts by mass, and 22 parts by mass, respectively.

[0081] (Comparative Example 9) The resin composition of Comparative Example 9 was prepared in the same manner as in Example 8, except that 3 parts by mass of hydrotalcite C were added instead of hydrotalcite B.

[0082] (Comparative Example 10) The resin composition of Comparative Example 10 was prepared in the same manner as in Example 8, except that 3 parts by mass of hydrotalcite D were added instead of hydrotalcite B.

[0083] <Fabrication and evaluation of press-formed products> The resin compositions of Examples 8-14 and Comparative Examples 6-10 were press-molded at 190°C for 5 minutes to produce 2 mm thick sheet-like press-molded articles. Furthermore, the water resistance of the press-molded articles thus produced was evaluated by measuring the volume change rate according to the <Water Resistance Test> described above. The results of the volume change rate measurement in the water resistance test, along with the formulations of the resin compositions of Examples 8-14 and Comparative Examples 6-10, are shown in Table 2 below.

[0084] [Table 2]

[0085] (Example 15) <Preparation of fluororubber composition> The composition of Example 15 (rubber composition) was prepared by mixing 100 parts by mass of fluororubber (manufactured by Daikin Industries, Ltd., fluorine concentration: 66 wt%, raw rubber Mooney viscosity ML1+10 (121℃) = 41) as a polymer component with 3 parts by mass of the above-mentioned hydrotalcite B, 6 parts by mass of calcium hydroxide (manufactured by Omi Chemical Industry Co., Ltd., Calvit), and 20 parts by mass of MT carbon black (manufactured by Cancarb Limited) as a reinforcing material, and kneading using an 8-inch roll.

[0086] (Comparative Example 11) A rubber composition for Comparative Example 11 was prepared in the same manner as in Example 15, except that 3 parts by mass of magnesium oxide (Kyowa Mag 150, manufactured by Kyowa Chemical Industry Co., Ltd.) was added instead of hydrotalcite B.

[0087] <Fabrication and Evaluation of Cumulated Molded Products> The rubber compositions of Example 15 and Comparative Example 11 were press-vulcanized at 170°C for 15 minutes to produce 2 mm thick vulcanized molded sheets. Furthermore, the water resistance of the vulcanized molded sheets thus produced was evaluated by measuring the volume change rate according to the <Water Resistance Test> described above. The results of the volume change rate measurement in the water resistance test, along with the formulations of the rubber compositions of Example 15 and Comparative Example 11, are shown in Table 3 below.

[0088] [Table 3]

[0089] (Example 16) <Preparation of ethylene propylene diene rubber composition> The polymer component consists of 100 parts by mass of ethylene propylene diene rubber (manufactured by Mitsui Chemicals, Inc., natural rubber Mooney viscosity ML1+4 (100℃) = 40), 5 parts by mass of the above hydrotalcite B, 1 part by mass of stearic acid (manufactured by Shin Nippon Rika Co., Ltd., stearic acid 50S) as a lubricant, 50 parts by mass of process oil (manufactured by Idemitsu Kosan Co., Ltd., PW-380), and three types of carbon black as reinforcing materials: 45 parts by mass of SRF carbon black (manufactured by Asahi Carbon Co., Ltd., Asahi #35) and MT carbon black (Cancarb The composition of Example 16 (rubber composition) was prepared by blending 45 parts by mass of (manufactured by Limited) and 30 parts by mass of FEF carbon black (manufactured by Tokai Carbon Co., Ltd., Seast SO), 2 parts by mass of poly(2,2,4-trimethyl-1,2-dihydroquinoline) (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Nocrack 224-S) as a heat-resistant anti-aging agent, 7 parts by mass of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (manufactured by NOF Corporation, Perhexa 25B-40) as a peroxide, and 1.5 parts by mass of triallyl isocyanurate (manufactured by Mitsubishi Chemical Corporation, TAIC) as a crosslinking accelerator, and kneading using an 8-inch roll.

[0090] (Comparative Example 12) The rubber composition of Comparative Example 12 was prepared in the same manner as in Example 16, except that 5 parts by mass of zinc oxide (2 types of zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd.) were added instead of hydrotalcite B.

[0091] <Fabrication and Evaluation of Cumulated Molded Products> The rubber compositions of Example 16 and Comparative Example 12 were press-vulcanized at 180°C for 15 minutes to produce 2 mm thick vulcanized molded sheets. Furthermore, the water resistance of the vulcanized molded sheets thus produced was evaluated by measuring the volume change rate according to the <Water Resistance Test> described above. The results of the volume change rate measurement in the water resistance test, along with the formulations of the rubber compositions of Example 16 and Comparative Example 12, are shown in Table 4 below.

[0092] [Table 4]

[0093] <Powder X-ray diffraction of hydrotalcite> The hydrotalcite A to E used in each of the above examples and comparative examples were analyzed by powder X-ray diffraction, and their respective powder X-ray diffraction patterns were confirmed. The powder X-ray diffraction patterns of each hydrotalcite are shown in Figure 1. In Figure 1, the symbols HT-A, HT-B, HT-C, HT-D, and HT-E attached to the five diffraction patterns arranged vertically represent hydrotalcite A, B, C, D, and E, respectively, and the symbols P1, P2, and P3 represent the first peak, second peak, and third peak, respectively.

[0094] As shown in Figure 1, hydrotalcite A (HT-A), hydrotalcite B (HT-B), and hydrotalcite E (HT-E) used in the examples all exhibited a unique powder X-ray diffraction pattern with a first peak (P1) where 2θ starts at 28°~32° and ends at 38°~41°, a second peak (P2) where 2θ starts at 38°~41° and ends at 45°~47°, and a third peak (P3) where 2θ starts at 59°~61° and ends at 64°~66°. On the other hand, hydrotalcite C (HT-C) used in the comparative example did not have the second peak (P2), and hydrotalcite D (HT-D) also used in the comparative example did not have the first peak (P1). It was confirmed that none of the hydrotalcites exhibited the aforementioned unique powder X-ray diffraction pattern.

[0095] As shown in Tables 1 to 4, a comparison of Examples 1 to 16 and Comparative Examples 1 to 12 revealed that a composition containing 1 to 12 parts by mass of hydrotalcite represented by the above chemical formula (1) and having the above-described characteristic powder X-ray diffraction pattern, per 100 parts by mass of polymer, can produce molded articles and vulcanized molded articles with excellent water resistance. [Industrial applicability]

[0096] Because the composition of the present invention has excellent water resistance, it can be suitably used in various fields such as automotive parts (e.g., rubber components such as sealing materials), hose materials, covering materials, belt materials, building materials, gaskets, and other resin and rubber products. [Explanation of Symbols]

[0097] P1 (First Peak) P2 (Second Peak) P3 (Third Peak) HT-A Hydrotalcite A HT-B Hydrotalcite B HT-C Hydrotalcite C HT-D Hydrotalcite D HT-E Hydrotalcite E

Claims

1. A composition comprising a polymer and hydrotalcite, The hydrotalcite is represented by the following chemical formula (1), and has a first peak, a second peak, and a third peak in its powder X-ray diffraction pattern. The 2θ of the first peak described above starts from 28° to 32° and ends from 38° to 41°. The 2θ of the aforementioned second peak starts from 38° to 41° and ends from 45° to 47°. The third peak is hydrotalcite with 2θ starting from 59° to 61° and ending from 64° to 66°. The composition contains 1 to 12 parts by mass of hydrotalcite per 100 parts by mass of the polymer, The aforementioned polymer contains a halogen-based polymer, The composition is characterized in that the halogenated polymer comprises at least one halogenated polymer selected from chloroprene rubber, chloroprene rubber containing acrylonitrile monomer units, chlorinated butyl rubber, brominated butyl rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, and fluororubber. M ２＋ ｘ Zn ｙ ・M ３＋ ｚ O ｘ＋ｙ＋（３／２）ｚ (1) (In the formula, M ２＋ represents at least one divalent metal ion, M ３＋ (where represents at least one trivalent metal ion, and x, y, and z represent numbers satisfying 0 < x ≤ 0.5, 0 < y ≤ 0.2, and 0 < z ≤ 0.4, respectively.)

2. A composition comprising a polymer and hydrotalcite, The hydrotalcite is represented by the following chemical formula (1), and has a first peak, a second peak, and a third peak in its powder X-ray diffraction pattern. The 2θ of the first peak described above starts from 28° to 32° and ends from 38° to 41°. The 2θ of the aforementioned second peak starts from 38° to 41° and ends from 45° to 47°. The third peak is hydrotalcite with 2θ starting from 59° to 61° and ending from 64° to 66°. The composition contains 1 to 12 parts by mass of hydrotalcite per 100 parts by mass of the polymer, The aforementioned polymer includes a non-halogenated polymer, The composition is characterized in that the non-halogenated polymer comprises at least one non-halogenated polymer selected from ethylene propylene diene rubber, styrene butadiene rubber, natural rubber, isoprene rubber, silicone rubber, butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, and acrylic rubber. M 2+ x Zny ・M 3+ z O x+y+(3 / 2)z (1) (In the formula, M²⁺ represents at least one divalent metal ion, M³⁺ represents at least one trivalent metal ion, and x, y, and z represent numbers that satisfy 0 < x ≤ 0.5, 0 < y ≤ 0.2, and 0 < z ≤ 0.4, respectively.)

3. A composition comprising a polymer and hydrotalcite, The hydrotalcite is represented by the following chemical formula (1), and has a first peak, a second peak, and a third peak in its powder X-ray diffraction pattern. The 2θ of the first peak described above starts from 28° to 32° and ends from 38° to 41°. The 2θ of the aforementioned second peak starts from 38° to 41° and ends from 45° to 47°. The third peak is hydrotalcite with 2θ starting from 59° to 61° and ending from 64° to 66°. The composition contains 1 to 12 parts by mass of hydrotalcite per 100 parts by mass of the polymer, The specific surface area of the hydrotalcite is 120 m ２ / g to 250 m ２ / g, and the composition is characterized by this. M ２＋ ｘ Zn ｙ ・M ３＋ ｚ O ｘ＋ｙ＋（３／２）ｚ (1) (In the formula, M ２＋ represents at least one divalent metal ion, M ３＋ (where represents at least one trivalent metal ion, and x, y, and z represent numbers satisfying 0 < x ≤ 0.5, 0 < y ≤ 0.2, and 0 < z ≤ 0.4, respectively.)

4. The composition according to claim 3, characterized in that the polymer includes a halogen-based polymer.

5. The composition according to claim 4, characterized in that the halogen-based polymer includes a vinyl chloride resin.

6. The composition according to claim 3, characterized in that the polymer comprises a non-halogenated polymer.

7. The composition according to claim 1 or 2, characterized in that the specific surface area of ​​the hydrotalcite is 120 m² / g to 250 m² / g.

8. The hydrotalcite is M in the chemical formula (1). ２＋ is Mg ２＋ And M ３＋ Al ３＋ The composition according to any one of claims 1 to 7, characterized in that it is the same as the one described above.

9. A vulcanized product of the composition according to claim 1, 2, or 7.

10. A vulcanized molded article using the vulcanized material described in claim 9.

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