JP2012251041A - Method for producing modified silicone resin-foamed body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a modified silicone resin-foamed body, which includes the steps of pouring a foamable material that comprises: a curing agent (A) having at least two hydrosilyl groups in a molecular chain thereof; a polymer (B) which has at least one alkenyl group in a molecular chain thereof and comprises an oxyalkylene unit as a repeating unit constituting a main chain; a hydrosilylation catalyst (C); and a foaming agent (D), into a mold die, and heating the foamable material to produce the modified silicone resin foamed body having an excellent shape easily and with satisfactory productivity.SOLUTION: Heat transmission from the upper surface of the mold die or the upper surface and side surface thereof is suppressed by using a thermal-insulating material to obtain the modified silicone resin-foamed body having the excellent shape.

Description

  The present invention relates to a method for producing a modified silicone foam.

  A foam using a modified silicone resin has been proposed as a soft foam having good tactile sensation and excellent flexibility (Patent Document 1). The foam using the modified silicone resin has better tactile sensation than the foam made of polyurethane, which is a conventional soft foam, and has excellent flexibility such as low hardness and low rebound resilience, and toxicity. Is not used, and is suitable as a material for bedding and various cushioning materials.

  Curing agent (A) having at least two hydrosilyl groups in the molecular chain, polymer having at least one alkenyl group in the molecular chain, and a repeating unit constituting the main chain consisting of oxyalkylene units (B ), A hydrosilylation catalyst (C), and a foaming agent (D) are poured into a mold and heated to cause the foaming agent (D) to generate gas by thermal decomposition or chemical reaction. The hydrosilylation reaction by the hydrosilyl group of the curing agent (A) and the alkenyl group of the polymer (B) proceeds, and the curing agent (A) and the polymer (B) form (cured) a network (crosslinked) structure. Thus, it can be produced by foam curing.

  In the heating method using hot air, heating of the foamable material inside the mold is performed by heat transfer from the mold to the foamable material. Therefore, the heat transfer is performed in the vicinity of adjacent parts such as sides and corners inside the mold. There is a tendency that the heat area is increased and heated faster than the other portions, and the gelation of the foamable material proceeds faster than the other portions. In the gelled part, the flowability of the foamable material is low and the volume expansion due to foaming is small, but in the ungelled part adjacent to the gelled part, the gas generated from the gelled part also contributes to foaming. The portion where the S is slower tends to increase the volume expansion, resulting in non-uniform foaming.

  When this non-uniform foaming occurs, defects in the appearance of the molded body and the characteristics of the molded body, such as defective filling in the cavity and cell coalescence due to excessive gas generation, become a problem. In particular, when the mold die is thin, the difference in heat transfer rate to the mold die due to the direction of hot air greatly affects the difference in heating rate of the foamable material, and the above-mentioned non-uniform foaming tends to become more prominent.

International Publication No. 2008/117734

  An object of the present invention is to develop a method for producing a modified silicone resin foam having a good shape in a mold forming method in an oven.

  As a result of intensive studies to solve the above problems, the present inventors have suppressed the non-uniform foaming by suppressing heat transfer from the side surface and / or the upper surface of the mold, and have good shape. It has been found that a resin foam can be molded, and the effect is particularly remarkable when the mold is thin. That is, the present invention has the following configuration.

  1). Curing agent (A) having at least two hydrosilyl groups in the molecular chain, polymer having at least one alkenyl group in the molecular chain, and a repeating unit constituting the main chain consisting of oxyalkylene units (B ), A hydrosilylation catalyst (C), and a foaming agent (D), in a method for producing a modified silicone resin foam by heating in a mold, heat transfer from the upper surface of the mold is suppressed. A method for producing a modified silicone resin foam, characterized by comprising means.

  2). 1. The production of a modified silicone resin foam according to 1), wherein a member made of a material whose heat conduction is suppressed is lower in material than the material of the bottom surface of the mold, is provided on the upper surface of the mold. Method.

  3). The method for producing a modified silicone resin foam according to 1) or 2), wherein means for suppressing heat transfer is also provided on part or all of the side surface of the mold.

  4). The modified silicon according to any one of 1) to 3), wherein a member having a lower thermal conductivity than the material of the bottom surface of the mold die is used as means for suppressing heat transfer, and the member is a heat insulating material. A process for producing a resin foam.

5). The method for producing a modified silicone resin foam according to any one of 1) to 4), wherein the mold has a thickness of 0.5 mm to 3 mm.

  According to the present invention, a modified silicone resin foam having a good shape can be produced simply and with good productivity.

It is the schematic of the mold type | mold 1 used by a comparative example. 1 is a schematic view of a mold 2 used in Example 1. FIG. 3 is a schematic view of a mold 3 used in Example 2. FIG.

  The foamable liquid resin composition of the present invention includes a curing agent (A) having at least two hydrosilyl groups in the molecular chain, a repeating unit having at least one alkenyl group in the molecular chain and constituting the main chain. Is a foamable liquid comprising a polymer (B) comprising an oxyalkylene-based unit, a hydrosilylation catalyst (C), and a foaming agent (D) and having a hydrosilyl group content of 0.5 to 15 moles per mole of alkenyl groups. It is a resin composition, and a foam is a foam formed by foaming the composition.

-About hardening | curing agent (A) The hardening | curing agent (A) which has at least 2 hydrosilyl group in the molecular chain in this invention has at least 2, preferably 3, especially 4 or more hydrosilyl groups in a molecular chain. Have The upper limit of the number of hydrosilyl groups is preferably 100, more preferably 75, and still more preferably 60. In the curing agent (A) in the present invention, the hydrosilyl group in the molecular chain reacts with at least one alkenyl group present in the molecular chain of the polymer (B) to be cured.

  When the number of hydrosilyl groups in the curing agent (A) is small, the curing rate when the liquid resin composition of the present invention is cured by a hydrosilylation reaction is slow, and the balance between the foaming and curing rates cannot be balanced, which is poor. It becomes a structure. Further, when the number of hydrosilyl groups in the curing agent (A) is increased, the stability of the curing agent (A), that is, the stability of the liquid resin composition is deteriorated, or a large amount of hydrosilyl groups are present in the foam after curing. And tend to lose its flexibility gradually over time.

In the present invention, the number of functional groups of the hydrosilyl group can also be referred to as the number of H atoms directly bonded to Si atoms. For example, in the case of SiH ₂ , the number of functional groups of the hydrosilyl group is two. When the number of H atoms bonded to one Si atom is one, the curability is improved, and it is also preferable from the viewpoint of flexibility.

  The number average molecular weight Mn of the curing agent (A) in the present invention is preferably 30000 as the upper limit, more preferably 20000, and more preferably 15000 or less from the viewpoint of reactivity with the polymer (B), dispersibility, workability and the like. More preferably. In consideration of the compatibility and reactivity with the polymer (B), the number average molecular weight Mn of the curing agent (A) is more preferably 300 or more and 10,000 or less, and particularly preferably 500 or more and 6,000 or less. The number average molecular weight Mn can be measured by various methods, but is easily measured by gel permeation chromatography (GPC).

  The structure of the curing agent (A) in the present invention is not particularly limited as long as it has at least two hydrosilyl groups in the molecular chain, whether the hydrosilyl group is in the main chain or in the side chain of the molecule. The molecular chain is not particularly limited, but organohydrogenpolysiloxane is preferred from the viewpoint of availability of raw materials and reactivity.

  In the organohydrogenpolysiloxane, the substituted or unsubstituted monovalent hydrocarbon group bonded to the Si atom is preferably an alkyl group, an aryl group, or an aralkyl group. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, and decyl group. It is done. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. Examples of the aralkyl group include aralkyl groups such as a benzyl group, a phenylethyl group, and a phenylpropyl group.

  Examples of the organohydrogenpolysiloxane include trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both ends, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, and trimethylsiloxy group-blocked methylhydrogensiloxane at both ends. -A diphenylsiloxane copolymer, a trimethylsiloxy group-blocked methyl hydrogen siloxane, a diphenylsiloxane, a dimethylsiloxane copolymer, etc. are mentioned.

  A hardening | curing agent (A) can be synthesize | combined by a well-known method, and what is marketed can use a commercial item as it is. Examples of commercially available organohydrogenpolysiloxane include KF-99, KF-9901 (manufactured by Shin-Etsu Chemical Co., Ltd.), HMS-151, HMS-301, HMS-991 (manufactured by Gelest), and SH1107 (Toray Industries, Inc.). -Dow Corning Co., Ltd.), TSF484 (Mentive Performance Materials Co., Ltd.), H-Siloxane (Asahi Kasei Wacker Silicone Co., Ltd.), etc. can be mentioned.

  In addition, in order to ensure compatibility with the polymer (B) and to adjust the amount of hydrosilyl group, organohydrogenpolysiloxane is changed to α-olefin, styrene, α-methylstyrene, allyl alkyl ether, allyl alkyl ester, allyl phenyl. Examples thereof include compounds modified with ether, allyl phenyl ester or the like. These may be used alone or in combination of two or more.

-About polymer (B) The polymer (B) in this invention is a polymer which has at least 1 alkenyl group in a molecular chain, and the repeating unit which comprises a principal chain consists of an oxyalkylene type unit. The alkenyl group is not particularly limited as long as it is a group containing a carbon-carbon double bond that is active for hydrosilylation reaction. The alkenyl group is preferably an aliphatic unsaturated hydrocarbon group having 2 to 20 carbon atoms, more preferably 2 to 4 carbon atoms (eg, vinyl group, allyl group, methylvinyl group, propenyl group, butenyl group, pentenyl group). Group, hexenyl group, etc.), preferably a cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms, more preferably 3 to 6 carbon atoms (eg, cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, etc.) ), A methacryl group and the like.

  The polymer (B) is a component that is cured by a hydrosilylation reaction with the curing agent (A). Since the polymer (B) has at least one alkenyl group in the molecular chain, the hydrosilylation reaction takes place and the polymer is cured. To do. The number of functional groups of the alkenyl group contained in the polymer (B) is at least one from the viewpoint of hydrosilylation reaction with the curing agent (A), but from the viewpoint of curability and flexibility, the main chain or branched It is preferable that alkenyl groups exist at both ends of the molecular chain. The bonding mode of the alkenyl group to the polyoxyalkylene polymer is not particularly limited, and examples thereof include a direct bond of an alkenyl group, an ether bond, an ester bond, a carbonate bond, a urethane bond, and a urea bond.

  The polymer (B) in the present invention is produced by polymerizing a compound having two or more active hydrogens as a starting material for forming the main chain because the repeating unit constituting the main chain is an oxyalkylene unit. be able to. For example, the polymer (B) can be produced by polymerizing alkylene oxide having 2 to 4 carbon atoms using ethylene glycol, propylene glycol, bisphenol compound, glycerin, trimethylolpropane, pentaerythritol and the like. .

  Specific examples of the main chain of the polymer (B) in the present invention include, for example, polyethylene oxide, polypropylene oxide, polybutylene oxide; two or more random or block copolymers selected from ethylene oxide, propylene oxide, and butylene oxide. , Etc. From the viewpoints of flexibility and touch, the repeating unit of the main chain is more preferably polypropylene oxide.

  The structure of the polymer (B) in the present invention may be linear or may have a branched structure in a range where the branching is smaller than the molecular weight of the main chain. It is preferable from the viewpoint of flexibility. The method for producing the polymer (B) is not particularly limited, and examples thereof include a method of introducing an alkenyl group after obtaining a polyoxyalkylene polymer. In this case, various known production methods can be applied to the oxyalkylene polymer, and a commercially available polyoxyalkylene polymer may be used.

  In addition, a method of introducing an alkenyl group into a polyoxyalkylene polymer is also known. For example, a monomer having an alkenyl group (eg, allyl glycidyl ether) and a monomer for synthesizing a polyoxyalkylene polymer are copolymerized. Or a functional group having reactivity to the functional group in a polyoxyalkylene polymer in which a functional group (eg, hydroxyl group, alkoxide group) has been introduced into a desired portion (end of main chain, etc.) in advance. And a method of reacting a compound having both a group and an alkenyl group (eg, acrylic acid, methacrylic acid, vinyl acetate, acrylic acid chloride, etc.).

  As for the molecular weight of the polymer (B) in the present invention, the number average molecular weight Mn is preferably 15000 or more, and more preferably 17000 or more, from the viewpoint of balance between flexibility, touch and reactivity. The upper limit of the number average molecular weight Mn is not particularly limited, but is preferably 50000 or less, more preferably 45000 or less, and further preferably 40000 or less.

  In the present invention, the content of the curing agent (A) and the polymer (B) is such that the hydrosilyl group content in the curing agent (A) is the alkenyl group in the polymer (B) from the viewpoints of touch and flexibility. It is preferable to mix | blend so that it may become 0.5 mol or more and 15 mol or less per mol, and it is more preferable to mix | blend so that it may become 0.8 mol or more and 12.5 mol or less.

  When the hydrosilyl group content is low, the curing rate when the foamable liquid resin composition of the present invention is cured by the hydrosilylation reaction is slowed, and the balance between foaming and curing cannot be achieved, resulting in a defective structure. In addition, when the hydrosilyl group content increases, a large amount of hydrosilyl groups are likely to remain in the foam even after curing, and the curing reaction (crosslinking) proceeds due to the influence of temperature and the like even after forming the product form. Tend to. For this reason, it becomes a cause of deterioration of tactile sensation and flexibility over time and compression residual strain.

-About hydrosilylation catalyst (C) As long as it can be used as a hydrosilylation catalyst as a hydrosilylation catalyst (C) in this invention, there is no restriction | limiting in particular, Arbitrary things can be used. Specific examples of the hydrosilylation catalyst (C) include platinum carriers; alumina, silica, carbon black and other carriers supported on solid platinum; chloroplatinic acid; complexes of chloroplatinic acid and alcohols, aldehydes, ketones, etc. Platinum-olefin complexes and platinum-vinylsiloxane complexes; platinum-phosphine complexes; platinum-phosphite complexes; dicarbonyldichloroplatinum and the like.

The content of the hydrosilylation catalyst (C) in the present invention is preferably from 10 ⁻⁸ mol to 10 ⁻¹ mol, preferably from 10 ⁻⁶ mol to 10 ⁻² mol, relative to 1 mol of the alkenyl group of the polymer (B). Is more preferable. If the content of the hydrosilylation catalyst (C) is low, curing may not proceed sufficiently. Moreover, when there is much content of a hydrosilylation catalyst (C), control of hardening of a liquid resin composition may be difficult, and the obtained modified silicone resin foam may be colored.

-About foaming agent (D) The foaming agent (D) in the present invention is preferably a chemical foaming agent that decomposes by heating to generate an inorganic gas such as carbon dioxide or nitrogen gas. Type foaming agents, inorganic pyrolytic foaming agents, inorganic reactive foaming agents, and the like.
Examples of the organic pyrolytic foaming agent include azo compounds, nitroso compounds, hydrazine derivatives, semicarbazide compounds, tetrazole compounds, and organic acids. Examples of the inorganic pyrolytic foaming agent include bicarbonate, carbonate, organic acid salt, and nitrite. Examples of the inorganic reactive foaming agent include a combination of bicarbonate and an organic acid or an organic acid salt.

Examples of the azo compound include azodicarbonamide (ADCA), azobisisobutyronitrile (AIBN), barium azodicarboxylate, diazoaminobenzene, and the like.
Examples of the nitroso compound include dinitrosopentamethylenetetramine (DPT).

  Examples of the hydrazine derivative include p, p'-oxybis (benzenesulfonylhydrazide) (OBSH), paratoluenesulfonyl hydrazide (TSH), hydrazodicarbonamide (HDCA), and the like.

Examples of the semicarbazide compound include p-toluenesulfonyl semicarbazide. Examples of the tetrazole compound include 5-phenyltetrazole, 1-H tetrazole salt, 1,4-bistetrazole and the like.
Examples of the organic acid include polyvalent carboxylic acids such as citric acid, oxalic acid, fumaric acid, phthalic acid, malic acid, and tartaric acid.

Examples of the organic pyrolytic foaming agent further include trihydrazinotriazine. Examples of the bicarbonate include sodium bicarbonate and ammonium bicarbonate.
Examples of the carbonate include sodium carbonate and ammonium carbonate.
Examples of the organic acid salt include metal salts such as sodium, potassium, calcium, magnesium, ammonium, aluminum, and zinc of the organic acid.
Examples of nitrites include ammonium nitrite.

  Of these, the foaming agent (D) of the present invention is preferably decomposed in a temperature range where the curing reaction (hydrosilylation reaction) of the curing agent (A) and the polymer (B) proceeds appropriately. A mixture of a salt and an organic acid is preferred. Examples of the bicarbonate include sodium bicarbonate and ammonium bicarbonate. Examples of the organic acid include citric acid, oxalic acid, fumaric acid, phthalic acid, malic acid, and tartaric acid. Further, a mixture of a bicarbonate and a metal salt of an organic acid can be preferably used as well.

  The content of the foaming agent (D) is, for example, in the case of a chemical foaming agent comprising a bicarbonate and an organic acid or an organic acid salt, the amount of the bicarbonate is 1 weight with respect to 100 parts by weight of the polymer (B). Is preferably 20 parts by weight or more and 20 parts by weight or less, more preferably 2 parts by weight or more and 15 parts by weight or less. The ratio of bicarbonate to organic acid or organic acid salt is preferably such that bicarbonate / organic acid or organic acid salt (weight ratio) is ¼ or more and 3 or less, and １ ／ or more and 2 or less. Is more preferable. If the content of bicarbonate is low or the ratio of bicarbonate to organic acid is low, the amount of carbon dioxide that is thermally decomposed is small, and the expansion ratio may decrease. Also, if the content of bicarbonate is high or the ratio of bicarbonate to organic acid is high, the amount of carbon dioxide gas that is thermally decomposed is large, the balance between foaming and curing is lost, and foaming cells are enlarged, resulting in poor foaming. May become a body.

・ About other additives.
The modified silicone resin foam of the present invention includes a non-reactive lubricant, a light-resistant stabilizer, an ultraviolet absorber, a storage stability improver, a bubble regulator, a surfactant, a plastic, unless the effects of the present invention are impaired. An agent or the like may be added as necessary.

  The modified silicone resin foam of the present invention contains a non-reactive lubricant, thereby reducing the friction and adhesion in the foam cell of the modified silicone resin foam, and obtaining a foam having a desired tactile sensation and flexibility. Can do. As the non-reactive lubricant, a liquid lubricant is preferable.

  Specific examples of the liquid lubricant include animal and vegetable oils such as paraffinic mineral oil, naphthenic mineral oil, and fatty acid glyceride; olefinic lubricants having an alkyl structure such as poly-1-decene and polybutene; alkyl fragrances having an aralkyl structure Group compound lubricants; polyalkylene glycol lubricants; ether lubricants such as polyalkylene glycol ethers, perfluoropolyethers, polyphenyl ethers; fatty acid esters, fatty acid diesters, polyol esters, silicate esters, phosphate esters, etc. Ester lubricants having the following ester structure: silicone oils such as dimethylpolysiloxane and silicone oils in which a part of methyl groups of dimethylpolysiloxane are substituted with polyether groups, phenyl groups, alkyl groups, aralkyl groups, fluorinated alkyl groups, etc. Corn-based lubricant; and fluorine-containing lubricant such as chlorofluorocarbon and the like. Among these, in the present invention, a silicone-based lubricant is particularly preferable from the viewpoints of reduction in coefficient of friction in the foamed cell, dispersibility, workability, safety, and the like.

  In the present invention, the amount of the non-reactive lubricant added is preferably 1 part by weight or more, more preferably 2 parts by weight or more, and still more preferably 5 parts by weight or more with respect to 100 parts by weight of the polymer (B). If the addition amount of the non-reactive lubricant is small, the suppression of friction and adhesion in the foam cell is insufficient, and it is difficult to obtain desired tactile sensation and flexibility. The upper limit of the non-reactive lubricant is not particularly limited, but is preferably 20 parts by weight or less, more preferably 15 parts by weight or less. When the amount is too large, bleeding of the non-reactive lubricant to the outside of the system tends to occur.

  Examples of the light-resistant stabilizer include hindered phenol antioxidants and hindered amine light stabilizers containing no sulfur atom, phosphorus atom, primary amine, or secondary amine. Here, the light-resistant stabilizer is a function that absorbs light having a wavelength in the ultraviolet region and suppresses the generation of radicals, or a function that captures radicals generated by light absorption and converts them into heat energy to render them harmless. And a compound that enhances stability to light.

  Although it does not specifically limit as a ultraviolet absorber, A benzoxazine type ultraviolet absorber, a benzophenone type ultraviolet absorber, a benzotriazole type ultraviolet absorber, a triazine type ultraviolet absorber etc. are illustrated. Here, the ultraviolet absorber is a compound having a function of absorbing light having a wavelength in the ultraviolet region and suppressing generation of radicals.

  The addition amount of the light-resistant stabilizer and the ultraviolet absorber in the present invention is preferably 0.01 parts by weight or more and 5 parts by weight or less, and 0.1 parts by weight or more with respect to 100 parts by weight of the polymer (B). 3 parts by weight or less is more preferable, and 0.3 part by weight or more and 2.0 parts by weight or less is more preferable. When the addition amount of the light-resistant stabilizer and the ultraviolet absorber is within this range, it is easy to obtain the effect of suppressing the increase in surface tack over time.

  As the storage stability improver, any conventional stabilizer known as a storage stabilizer for the curing agent (A) can be used as long as it achieves the intended purpose. Preferable examples of the storage stability improver include, for example, a compound containing an aliphatic unsaturated bond, an organic phosphorus compound, an organic sulfur compound, a nitrogen-containing compound, a tin-based compound, and an organic peroxide. These may be used alone or in combination of two or more.

  Specifically, 2-benzothiazolyl sulfide, benzothiazole, thiazole, dimethylacetylene dicarboxylate, diethylacetylene dicarboxylate, 2,6-di-t-butyl-4-methylphenol, butylhydroxyanisole, vitamin E, 2- (4-morphodinyldithio) benzothiazole, 3-methyl-1-buten-3-ol, acetylenically unsaturated group-containing organosiloxane, acetylene alcohol, 3-methyl-1-butyn-3-ol 2-methyl-3-butyn-2-ol, diallyl fumarate, diallyl maleate, diethyl fumarate, diethyl maleate, dimethyl maleate, 2-pentenenitrile, 2,3-dichloropropene, and the like.

The amount of the storage stability improver used in the present invention can be selected almost arbitrarily as long as it is uniformly dispersed in the curing agent (A) and the polymer (B), but the SiH group in the curing agent (A) can be selected. It is preferably used in the range of 10 ⁻⁶ mol or more and 10 ⁻¹ mol or less with respect to ¹ mol. If the amount of the storage stability improver used is small, the storage stability of the curing agent (A) may not be sufficiently improved, and if it is large, the curability may be insufficient.

  If necessary, a foam regulator may be added to the modified silicone resin foam of the present invention. There are no particular limitations on the type of cell regulator, and commonly used, for example, inorganic solid powders such as talc, calcium carbonate, magnesium oxide, titanium oxide, zinc oxide, carbon black, silica, polyether modified silicone oil, etc. Silicone oil compounds, fluorine compounds, and the like. These may be used alone or in combination of two or more.

  In the present invention, the amount of use of the air conditioner is 0.1 parts by weight or more and 100 parts by weight or less when the total amount of the curing agent (A), polymer (B), and hydrosilylation catalyst (C) is 100 parts by weight. Is preferable, and 0.5 to 50 parts by weight is more preferable. In the present invention, a surfactant may be added for the purpose of improving the compatibility of the foamable liquid resin composition comprising the curing agent (A), the polymer (B), and the hydrosilylation catalyst (C). it can.

  Specific examples of surfactants include alkyl sulfates such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene alkyl ether acetate, lauryl trimethyl ammonium chloride, alkoxy chloride Propyltrimethylammonium chloride, dialkyldimethylammonium chloride, benzalkonium chloride solution, alkyldimethylaminoacetic acid betaine, alkyldimethylamine oxide, alkylcarboxymethylhydroxyethylimidazolinium betaine, alkylamidopropyl betaine, glycerin fatty acid ester, propylene glycol fatty acid ester, Nonionic surfactants, such as sorbitan fatty acid ester, etc. are mentioned. These may be used alone or in combination of two or more.

  In the present invention, for the purpose of improving the compatibility of the curing agent (A) and the non-reactive lubricant, a silicone surfactant such as a polyoxyalkylene-polydimethylsiloxane block copolymer may be added. it can.

  The polyoxyalkylene-polydimethylsiloxane block copolymer is not particularly limited. For example, in addition to an AB type diblock body, an ABA type triblock body, an (AB) n type multiblock body, a branched type, A pendant type, a star type, etc. are mentioned. In addition, specific structures of polyoxyalkylene include polyoxyethylene, polyoxypropylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer, and the terminal structure is also OH. Examples thereof include a base end, an ether end such as methoxy and t-butoxy, and a reactive allyl group end.

  In the present invention, a plasticizer can be added for the purpose of adjusting the flexibility and molding processability of the modified silicone resin foam. As the plasticizer in the present invention, a compound in which the repeating unit constituting the main chain is an oxyalkylene unit is used.

  Specific examples of the main chain include polyethylene oxide, polypropylene oxide, polybutylene oxide; two or more random or block copolymers selected from the group consisting of ethylene oxide, propylene oxide, and butylene oxide. These may be used alone or in combination of two or more. Of these, polypropylene oxide is preferable from the viewpoint of compatibility with the polymer (B).

  The molecular weight of the plasticizer in the present invention is preferably 1000 or more, more preferably 3000 or more as the number average molecular weight from the viewpoint of flexibility of the resulting modified silicone resin foam and prevention of outflow of the plasticizer to the outside of the system. If the number average molecular weight of the plasticizer is low, the plasticizer will flow out of the system over time due to heat, compression, etc., and the initial physical properties cannot be maintained over a long period of time, and there is a concern about an adverse effect on the tactile sensation. Further, if the number average molecular weight of the plasticizer becomes too high, the plasticizing effect cannot be obtained, and the viscosity becomes high and the workability deteriorates. Therefore, it is preferably less than 15000, more preferably 10,000 or less.

  The plasticizer in this invention may have a reactive functional group in the range which does not inhibit the hardening reaction of a hardening | curing agent (A) and a polymer (B). Examples of the reactive functional group of the plasticizer include vinyl group, allyl group, methyl vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, methacryl group, etc. Alkenyl group, hydroxyl group, amino group, carboxyl group, isocyanate group and the like.

  In addition, if the plasticizer of this invention can provide a softness | flexibility to a modified silicone resin foam, there will be no limitation in particular even if it is linear or branched. The addition amount of the plasticizer in the present invention is preferably 5 parts by weight or more and 150 parts by weight or less, more preferably 10 parts by weight or more and 120 parts by weight or less, and more preferably 20 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the polymer (B). More preferred are parts by weight or less.

If the amount of the plasticizer added is small, the effect of imparting flexibility may be insufficient, and if it is large, the mechanical strength of the modified silicone resin foam tends to be insufficient or the expansion ratio tends to decrease.
The manufacturing method of the plasticizer in this invention is not specifically limited, A well-known manufacturing method can be applied, and also a commercially available compound may be used.

  In the present invention, as necessary, a filler, a radical inhibitor, an adhesion improver, a flame retardant, a foam stabilizer, an acid or a basic compound (deleted because it is unclear), a storage stability improver, ozone Deterioration inhibitors, thickeners, coupling agents, conductivity-imparting agents, antistatic agents, radiation blocking agents, nucleating agents, phosphorus peroxide decomposing agents, pigments, metal deactivators, physical property modifiers, etc. It can add in the range which does not impair the objective and effect of this invention.

  In the method for producing a modified silicone resin foam of the present invention, a foamable material comprising a curing agent (A), a polymer (B), a hydrosilylation catalyst (C), and a foaming agent (D) is heated in a mold. Is a method for producing a modified silicone resin foam.

  During the heating, the foaming agent (D) generates gas by thermal decomposition or chemical reaction, while the hydrosilylation reaction by the hydrosilyl group of the curing agent (A) and the alkenyl group of the polymer (B) proceeds, and the curing agent ( A) and the polymer (B) can be produced by foaming and curing by forming (curing) a network (crosslinked) structure.

  The foamable material used in the present invention is liquid at normal temperature and substantially does not contain air bubbles before foaming, and the foam is formed by air bubbles generated after and / or during filling of the material into the mold. This relates to a molding method for obtaining In particular, the present invention relates to a method of obtaining a foam by generating bubbles from a foamable material after filling a mold.

  When obtaining a foamed molded article using a foamable material that does not substantially contain bubbles, it is necessary to allow for the volume expansion when filling the mold with the foamable material. Foam molding is performed in an open state. As a heating method, a method of heating a mold filled with a foamable material in a hot air furnace is often used.

  The present invention is characterized by providing means for suppressing heat transfer from the upper surface of the mold. By providing the mold with means for suppressing heat transfer from the upper surface of the mold, gelation of the free surface of the foamable material can be suppressed, and as a result, nonuniform foaming can be suppressed.

  In the present invention, by providing means for suppressing heat transfer on the side of the mold in addition to the upper surface of the mold, for example, when the mold is heated in a hot air oven, the temperature rise on the side of the mold is suppressed. This is preferable because the foam can be made more uniform. By providing a means for suppressing heat transfer at a specific part of the mold, the temperature rise of the foamable material in the vicinity of the adjacent sides and corners of the mold side and bottom is slowed down and gelled faster than other parts. It is possible to suppress non-uniform foaming.

  The amount of suppression of the temperature rise on the side surface of the mold due to the heat insulating material in the present invention needs to be adjusted according to the shape of the mold, but when the bottom surface temperature of the mold reaches the gelling temperature, the temperature of the side surface It is desirable to suppress so that it may become 5 degreeC or more lower than gelation temperature. If the temperature difference is smaller than 5 ° C., the effect of suppressing non-uniform foaming is not recognized so much, which is not desirable.

  The mold mold material that can be used in the method for producing a foam of the present invention is not particularly limited as long as it is a material having good thermal conductivity used in general resin molding, but the strength and heat capacity of the mold mold. From the point of view, it is preferably made of metal. Examples of metals that can be used include iron, aluminum, stainless steel, and copper. Among them, iron, aluminum, and stainless steel are preferable because they can be easily used.

  As a means for suppressing heat transfer that can be used in the method for producing a foam of the present invention, a plate made of the same material as the bottom of the mold can be provided on the upper surface of the mold, but the bottom of the mold It is preferable to use a material having lower thermal conductivity than Further, it is possible to employ a method in which a plate made of a material having a lower thermal conductivity than the bottom of the mold is attached to the upper surface of the mold or a predetermined location, or the material is used as a part of the mold. it can.

  Examples of the predetermined part of the mold include the upper surface and the side surface of the mold. In this case, the means for suppressing heat transfer is preferable because the foam obtained in the order of the upper surface and the side surface is reduced only in the upper surface and uneven foaming is reduced. Although it is preferable to provide it on all sides, it may not be provided on all sides such as focusing on the part where heating is easy to proceed (for example, the part where the wind hits well in a hot stove). The part provided with the means for suppressing heat can be appropriately selected and installed.

  As a means for suppressing heat transfer from the upper surface of the mold, for example, when heating using a hot air furnace, if the bottom portion is filled with a foamable material using a deep mold, the upper surface of the foamable material is used. Since hot air is less likely to hit compared to the case of using a mold mold with a shallow depth, it becomes a means for substantially suppressing heat transfer and can be employed as one of heat transfer suppressing means. However, there is a problem that productivity is lowered because the mold is larger than the obtained molded body.

  The method of the present invention is characterized in that at least means for suppressing heat transfer from the upper surface of the mold is provided, but the thickness of the mold is reduced by providing means for suppressing heat transfer also on the side surface. However, since the temperature unevenness of the mold caused by the difference in heat transfer rate from the hot air to the mold is less likely to occur, the thickness of the mold can be reduced. By reducing the thickness of the mold, the heating foam curing time is shortened as much as the heating time of the mold is shortened, so that the productivity of the modified silicone resin foam can be improved.

  The wall surface thickness of the mold is preferably 0.5 mm to 3 mm, more preferably 0.5 mm to 2 mm, and particularly preferably 0.5 mm to 1 mm. The thinner the thickness, the greater the amount of heat conduction to the foamed material and the shorter the time for heat-foaming curing. However, when the thickness is too thin, the strength of the mold is insufficient, which is not preferable. It is preferable that the mold is made of metal because the mold can be produced by sheet metal working or press working.

  The shape of the mold of the present invention is not particularly limited, and examples thereof include a polygon such as a rectangle, a square, a circle, an ellipse, and a rhombus, and a surface provided with arbitrary irregularities.

  As the material having a small thermal conductivity provided on the upper surface or the upper surface and the side surface of the mold die, a material having a lower thermal conductivity than the material used for the mold die, particularly the bottom surface of the mold die, is used. A heat insulating material can be used as the material. Although the material of the heat insulating material of this invention does not have limitation in particular, An organic heat insulating material and an inorganic heat insulating material can be used.

As the organic heat insulating material, wood, plastic sheet, synthetic resin foam, organic fiber, or organic fiber in sheet form can be used. As an inorganic heat insulating material, what made the inorganic fiber and the sheet form the inorganic fiber can be mention | raise | lifted.
Cellulose fibers can be used as the organic fiber material, and rock wool and glass fiber can be used as the inorganic fiber heat insulating material.

Examples of the synthetic resin foam include polystyrene foam, polyolefin foam, and urethane foam.
Examples of the plastic sheet include a silicon sheet, a fluororesin sheet, and a polyimide sheet. In view of high heat resistance, a sheet made of inorganic fibers and a plastic sheet are preferable.

  As the sheet-like inorganic fiber, a rock wool or glass fiber sheet is preferable, and as the plastic sheet, a silicon sheet, a fluororesin sheet, or a polyimide sheet is preferable. A glass fiber sheet, a silicon sheet, a fluororesin sheet, and a polyimide sheet are preferred from the viewpoint of ease of processing during installation in the mold.

  If the thickness of the heat insulating material that can be used is exemplified, it is preferable that the thickness is not less than the wall thickness of the mold used, and more preferably not less than three times the wall thickness. Moreover, if an upper limit is also illustrated, it is preferable that it is 50 times or less of the wall surface thickness of a mold, and also 20 times or less of wall surface thickness.

  As described above, it has been described that a material having a thermal conductivity smaller than that of the material used for the mold is used as a part of the mold (or a part thereof), but is provided at a predetermined position of the mold. May be provided. The mold die may be subjected to fluororesin processing on the inner surface of the die for the purpose of measuring releasability from the foam die. The processed film thickness can be made to be a means for suppressing heat transfer from the side surface by making the bottom surface thin and the side surface thick. Further, the above-described heat insulating material may be provided on the inner surface of the mold. In particular, if a fluororesin sheet is provided along the inner surface (a thin sheet may be provided on the bottom surface and a thick sheet may be provided on the side surface), the releasability of the foam is dramatically improved. Therefore, it is preferable.

  When foam curing is performed by heating the mold, the foaming agent (D) to be used decomposes in a temperature region where the curing reaction (hydrylylation) of the curing agent (A) and the polymer (B) proceeds appropriately. The temperature is preferably 40 ° C. or higher and 150 ° C. or lower, more preferably 50 ° C. or higher and 140 ° C. or lower, and particularly preferably 55 ° C. or higher and 130 ° C. or lower.

  Within this temperature range, curing and foaming of the foamable liquid resin composition proceed in a well-balanced manner, and a preferred modified silicone resin foam of the present invention is obtained. The time (heating time) for holding at the above temperature is not particularly limited, but it is preferable to hold at a temperature of 5 minutes to 3 hours, further 10 minutes to 2 hours, particularly 20 minutes to 90 minutes. The modified silicone resin foam of the invention is obtained.

  The modified silicone resin foam obtained by the method of the present invention is characterized in that a foam having a small variation in thickness is obtained. In particular, the thickness is 5 mm to 80 mm, more preferably 8 mm to 8 mm at the maximum thickness of the foam. It is effective for a thin foam of 70 mm, particularly 10 mm to 60 mm. By the method of the present invention, it is possible to reduce variations in thickness and characteristics of the obtained foam.

  The degree of reduction in the variation in thickness varies depending on the foaming ratio of the desired foam and the maximum thickness of the foam. If the degree of variation is illustrated as an example, 70% to 20% of the maximum thickness, It is also possible to keep it within 65% to 30%. Specifically, by the method of the present invention, the variation in the thickness of the foam obtained can be suppressed to 25 mm or less, and a modified silicone foam having a smaller thickness variation than the conventional foam can be produced.

  The modified silicone foam obtained by the method of the present invention is lightweight and excellent in flexibility, and thus is suitably used for pillows and cushions. The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

<Mold mold>
An iron mold 1 (inner dimensions: 200 mm × 200 mm × depth 50 mm, thickness 0.6 mm) whose surface is coated with a fluororesin shown in FIG. 1 was used as a comparative example. The upper part of the mold 1 is open.

  The mold 2 shown in FIG. 2 in which a fluororesin sheet having a thickness of 5 mm was installed on the upper part of the mold 1 was used in Example 1.

  The mold 3 shown in FIG. 3 was used in Example 2 in which a fluororesin sheet having a thickness of 5 mm was placed on the upper part of the mold 1 and a fluororesin sheet having a thickness of 5 mm was attached to the outer peripheral portion of the four side surfaces of the mold. .

<Compound used>
In the examples and comparative examples, the compounds shown in Table 1 were used.

Example 1
To a disposable cup, weigh out 1364 g of polymer (B), add 68 g of foaming agent (D-1) and 68 g of foaming agent (D-2), mix well with a spatula, and then mix with a BDM twin-screw mixer (stock )) And kneaded to produce a master batch. 321.2 g of this master batch was weighed into another disposable cup, and 1.9 g of the curing agent (A-1) and 8.0 g of the curing agent (A-2) were added thereto, followed by thorough mixing. Thereafter, 0.06 g of catalyst (C) was added and mixed by stirring to obtain a foamable material.

  Next, 340 g of a foamable material is injected into the mold 1, and a fluororesin sheet is placed on the mold 1 to obtain a mold 2. The mold 2 is placed in a heating furnace provided with a fan, The foamable material was foamed by heating at 100 ° C. for 60 minutes, and was cured while being filled in the cavity. After the heating was completed, the mold 2 was taken out from the heating furnace and removed from the mold 2 to obtain a foam.

(Example 2)
A foam was produced in the same steps as in Example 1 except that the mold die 3 was formed by placing a fluororesin sheet on the upper part of the mold die 1 infused with the foamable material and on the outer peripheral part 4 surface. It was.

(Comparative example)
Except that the mold 1 was used, a foam was produced in the same process as in Example 1 and used as a comparative example.

  The measurement and evaluation of the examples were performed under the following conditions and methods. The evaluation results are shown in Table 2.

<Foaming ratio>
The expansion ratio was calculated from the following formula.
Foaming ratio (times) = foam volume (cm ³ ) / volume of unfoamed foam material (cm ³ ) of the same weight (cm ³ )
<Foam thickness>
The thickness of the foam was measured using a height gauge.

  As shown in Table 2, the foam obtained in Example 1 had a foam thickness variation of 20 mm, and the foam of the comparative example obtained by heating at 100 ° C. for 60 minutes in the mold 1 (thickness of the foam). The thickness variation of the foam was smaller than the variation 43 mm).

  Further, the foam obtained in Example 2 had a foam thickness variation of 14 mm, and the foam thickness variation was smaller than that of Example 1.

Claims (5)

  Curing agent (A) having at least two hydrosilyl groups in the molecular chain, polymer having at least one alkenyl group in the molecular chain, and a repeating unit constituting the main chain consisting of oxyalkylene units (B ), A hydrosilylation catalyst (C), and a foaming agent (D), in a method for producing a modified silicone resin foam by heating in a mold, heat transfer from the upper surface of the mold is suppressed. A method for producing a modified silicone resin foam, characterized by comprising means.   2. The modified silicone resin foam according to claim 1, wherein the member for suppressing heat transfer is provided on the upper surface of the mold with a member made of a material having lower thermal conductivity than the material of the bottom surface of the mold. Production method.   The method for producing a modified silicone resin foam according to claim 1 or 2, wherein means for suppressing heat transfer is also provided on part or all of the side surface of the mold.   The modified silicon according to any one of claims 1 to 3, wherein a member having a lower thermal conductivity than the material of the bottom surface of the mold is used as means for suppressing heat transfer, and the member is a heat insulating material. A process for producing a resin foam. The method for producing a modified silicone resin foam according to any one of claims 1 to 4, wherein the mold has a thickness of 0.5 mm or more and 3 mm or less.

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