JP6526861B1 - Resin composition for molding and foam molded article - Google Patents

Abstract

The present invention provides a thermally expandable microcapsule capable of producing a foam molded article having an excellent appearance which is resistant to strong shear at the time of molding, has a high foaming ratio, and is resistant to yellowing. Provided are a molding resin composition and a foam molded article using the thermally expandable microcapsule. A thermally expandable microcapsule, wherein a volatile expansive agent is included as a core agent in a polymer shell, and the maximum foaming temperature is 170 ° C. or more, and the core agent is contained in an amount of 15 to 30 wt%, The shell comprises 70 to 90% by weight of polyacrylonitrile (I), 9.9 to 29.9% by weight of polymethacrylonitrile (II), and the shells other than polyacrylonitrile (I) and polymethacrylonitrile (II) A thermally expandable microcapsule, containing 0.1 to 3.0% by weight of the polymer (III), having a degree of gelation of 80% or more, and the core agent containing a hydrocarbon having a carbon number of 8 or more. 【Selection chart】 None

Description

The present invention is a thermally expandable microcapsule capable of producing a foam molded article having an excellent appearance that is resistant to strong shear during molding, has a high foaming ratio, and is resistant to yellowing, and the thermal expansion The present invention relates to a resin composition for molding, and a foam molded article using the microcapsules.

Thermally expandable microcapsules are used in a wide range of applications as a designability-imparting agent and a lightening agent, and are also used in foamed inks, paints for reducing weight such as wallpaper, and the like.
As such thermally expandable microcapsules, there are widely known thermoplastic shell polymers in which a volatile expanding agent which becomes gaseous at a temperature equal to or lower than the softening point of the shell polymer is contained. For example, Patent Document 1 discloses adding an oily mixed liquid obtained by mixing a volatile expanding agent such as a low-boiling aliphatic hydrocarbon with a monomer into an aqueous dispersion medium containing a dispersant together with an oil-soluble polymerization catalyst while stirring. There is disclosed a method of producing thermally expandable microcapsules containing a volatile expanding agent by carrying out suspension polymerization.

However, although the thermally expandable microcapsules obtained by this method can be thermally expanded at a relatively low temperature of about 80 to 130 ° C., the expanded microcapsules rupture or shrink when heated at a high temperature or for a long time As a result, the expansion ratio is lowered, so that the heat expandable microcapsules having excellent heat resistance can not be obtained.

On the other hand, Patent Document 2 discloses a polymer obtained from a polymerization component containing 80 to 97% by weight of nitrile monomer, 20 to 3% by weight of non-nitrile monomer and 0.1 to 1% by weight of trifunctional crosslinking agent. Discloses a method of producing thermally expandable microcapsules which contain volatile expansive agents.
Further, in Patent Document 3, a volatile expander is used, using a polymer obtained from a polymerization component containing 80% by weight or more of a nitrile monomer, 20% by weight or less of a non-nitrile monomer and 0.1 to 1% by weight of a crosslinking agent. Discloses a thermally expandable microcapsule in which is incorporated. In such thermally expandable microcapsules, methacrylic esters or acrylic esters are used as non-nitrile monomers.

The thermally expandable microcapsules obtained by these methods are superior in heat resistance to conventional microcapsules, and are considered not to foam at 140 ° C. or less. However, in fact, when heating is continued at 130 to 140 ° C. for about 1 minute, some of the microcapsules thermally expand, and the thermally expandable micro-particles have excellent heat resistance with a maximum foaming temperature of 180 ° C. or more. It was difficult to obtain a capsule.

Furthermore, in Patent Document 4, for the purpose of obtaining a thermally expandable microcapsule having a maximum foaming temperature of 180 ° C. or more, a homopolymer or copolymer of an ethylenically unsaturated monomer having a nitrile group of 85% by weight or more. A thermally expandable microcapsule is disclosed which comprises a coalescing shell polymer and a blowing agent having 50% by weight or more of isooctane.
With such thermally expandable microcapsules, although the maximum foaming temperature is a very high value, they are weak to the shear at the time of molding, and can not maintain the expanded state after that, and a long time in a high temperature region can not be maintained. Use was difficult.

Furthermore, Patent Documents 5 to 9 have good foaming performance in a wide foaming temperature range, particularly in a high temperature range (160 ° C. or more), by defining the monomers constituting the shell of the thermally expandable microcapsule, A thermally expandable microcapsule having a further improved heat resistance is disclosed.
However, although the thermally expandable microcapsules show high maximum foaming temperature values, problems occur in molding processing such as kneading molding, calendar molding, extrusion molding, injection molding and the like to which a strong shear force is applied. Particularly when used in injection molding, in the melt-kneading process, the heat resistance and strength problems of the thermally expandable microcapsule cause a phenomenon called so-called "stagnation" to occur or to be crushed, and further, a molded product obtained. My body sometimes turned yellow. Further, in the step of foaming the thermally expandable microcapsules, the thermally expandable microcapsules do not sufficiently foam due to the low expansion ratio and the uneven expansion ratio, and the resulting molded product has an appearance, a light weight, and the like. It has become inferior in terms of functionality such as sex.
In addition, white spots resulting from the aggregation of the heat-expandable microcapsules were generated on the surface of the foam, and the appearance of the foam was significantly impaired.
Therefore, there is a need for thermally expandable microcapsules that can produce a foam molded article that has excellent heat resistance and expansion ratio and that is resistant to yellowing and that has an excellent appearance.

Japanese Patent Publication No. 42-26524 Japanese Patent Publication No. 5-15499 Patent No. 2894990 European Patent Application No. 1149628 International Publication WO2003 / 099955 JP, 2009-113037, A JP, 2009-299071, A Unexamined-Japanese-Patent No. 2013-32542 JP, 2013-28818, A

The present invention is a thermally expandable microcapsule capable of producing a foam molded article having an excellent appearance that is resistant to strong shear during molding, has a high foaming ratio, and is resistant to yellowing, and the thermal expansion It is an object of the present invention to provide a molding resin composition and a foam molded article using the microcapsules. In addition, "it is hard to turn yellow" means that "it is hard to occur yellowing resulting from addition of a thermally expandable microcapsule".

The present invention contains 3 to 6 parts by weight of thermally expandable microcapsules and 60 to 80 parts by weight of plasticizer with respect to 100 parts by weight of vinyl chloride resin, and the thermally expandable microcapsules comprise a polymer shell. A thermally expandable microcapsule containing a volatile expansive agent as a core agent, having a maximum foaming temperature of 170 ° C. or more, and containing 15 to 30 wt% of the core agent, and the shell is polyacrylonitrile (I) 70 to 90% by weight, 9.9 to 29.9% by weight of polymethacrylonitrile (II), and 0.01 to 3 parts of polymers (III) other than polyacrylonitrile (I) and polymethacrylonitrile (II). The core agent is a molding resin composition containing 3.0% by weight, having a degree of gelation of 80% or more, and containing a hydrocarbon having a carbon number of 8 or more.
Hereinafter, the present invention will be described in detail.

As a result of intensive investigations by the present inventors, it is assumed that the shell configuration of the thermally expandable microcapsule contains a predetermined amount of the polymers (I) to (III), and the degree of gelation and the type and content of the core agent are predetermined. It was found that when in the range, it shows durability against strong shear during molding. In addition, it has been found that such thermally expandable microcapsules can produce a foam molded product having a high foaming ratio and an excellent appearance that is not easily yellowed, and the present invention has been completed.

The shell constituting the thermally expandable microcapsule of the present invention comprises 70 to 90% by weight of polyacrylonitrile (I), 9.9 to 29.9% by weight of polymethacrylonitrile (II), and the polyacrylonitrile (I) And 0.1 to 3.0% by weight of polymer (III) other than polymethacrylonitrile (II). In addition, content shows content in a shell.

The shell constituting the thermally expandable microcapsule contains polyacrylonitrile (I) and polymethacrylonitrile (II).
Thereby, the gas barrier properties of the shell can be improved.

The shell constituting the thermally expandable microcapsule contains 70 to 90% by weight of polyacrylonitrile (I). This makes it possible to maintain durability against shearing during molding where strong shearing force is applied.
The preferred lower limit of the acrylonitrile content is 75% by weight, and the preferred upper limit is 85% by weight.

The shell constituting the thermally expandable microcapsule contains 9.9 to 29.9% by weight of polymethacrylonitrile (II). Thereby, while maintaining the gas barrier properties of the shell, the heat resistance and the extensional viscosity can be increased, and the expansion ratio can be improved. The preferred lower limit is 15% by weight. Moreover, a preferable upper limit is 25 weight%.

The shell constituting the thermally expandable microcapsule contains 0.1 to 3.0% by weight of a polymer (III) other than polyacrylonitrile (I) and polymethacrylonitrile (II).
Examples of the polymer (III) include crosslinkable monomers having two or more double bonds in the molecule, radically polymerizable unsaturated carboxylic acid monomers, (meth) acrylates, vinylidene chloride, vinyl acetate, styrenic monomers, etc. Polymerized polymers may be mentioned.
Among them, a crosslinkable monomer having two or more double bonds in the molecule, a radically polymerizable unsaturated carboxylic acid monomer, and a polymer of (meth) acrylic acid ester are preferable.

The content of the polymer (III) is 0.1 to 3.0% by weight.
The lower limit of the content of the polymer (III) is 0.1% by weight, and the upper limit is 3.0% by weight. By setting the content of the polymer (III) to 0.1% by weight or more, the appearance of the foam molded article using the heat-expandable microcapsules is improved, and by setting the content to 3.0% by weight or less, the cell wall The gas barrier properties of the above can be improved, and the thermal expansion can be improved. The preferable lower limit of the content of the polymer (III) is 0.5% by weight, and the preferable upper limit is 1.5% by weight.

The crosslinkable monomer having two or more double bonds in the molecule has a role as a crosslinker. By containing the above-mentioned crosslinkable monomer, the strength of the shell can be strengthened, and the cell wall is less likely to break during thermal expansion.

Examples of the crosslinkable monomer include monomers having two or more radically polymerizable double bonds, and specific examples include, for example, divinylbenzene, di (meth) acrylate, trifunctional or higher (meth) acrylate, etc. .
Examples of the di (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and 1,4-butanediol di. Examples include (meth) acrylates and the like. In addition, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, dimethylol-tricyclodecanedi (meth) And the like. Furthermore, polyethylene glycol di (meth) acrylates having a weight average molecular weight of 200 to 600 may be used.
Examples of the trifunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate and triallyl formal tri (meth) acrylate. It can be mentioned. In addition, examples of the tetrafunctional or higher functional (meth) acrylate include pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.
Among these, trifunctional ones such as trimethylolpropane tri (meth) acrylate and bifunctional (meth) acrylates such as polyethylene glycol are preferably used. By using these, the shell composed mainly of acrylonitrile is relatively uniformly crosslinked, and the thermally expanded microcapsules are less likely to shrink even in a high temperature range exceeding 200 ° C., and the expanded state is easily maintained, so-called It is possible to suppress the phenomenon called "settle".

The lower limit of the content of the polymer of the crosslinkable monomer in the shell constituting the thermally expandable microcapsule is preferably 0.01% by weight, and the upper limit is preferably 1.0% by weight. By setting the content to 0.01% by weight or more, the effect as a crosslinking agent can be sufficiently exhibited, and by setting the content to 1.0% by weight or less, the thermally expandable microcapsule It becomes possible to improve the foaming ratio. The preferable lower limit of the content is 0.02% by weight, and the preferable upper limit is 0.06% by weight.

As said radically polymerizable unsaturated carboxylic acid monomer, it has a carboxyl group and a C3-C8 radically polymerizable unsaturated carboxylic acid monomer is preferable. As the radically polymerizable unsaturated carboxylic acid monomer having 3 to 8 carbon atoms, one having one or more free carboxyl groups for ionic crosslinking per molecule can be used.
Specifically, for example, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, cinnamic acid, etc., unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid, citraconic acid, chloromaleic acid, etc. And their anhydrides. In addition, monoesters and derivatives of unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate and the like can be mentioned. These may be used alone or in combination of two or more. Among these, acrylic acid, methacrylic acid, maleic acid, maleic anhydride and itaconic acid are particularly preferable.

As the (meth) acrylic acid ester, methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and n-butyl methacrylate, or alicyclic and aromatic compounds such as cyclohexyl methacrylate, benzyl methacrylate and isobornyl methacrylate Ring-heterocycle-containing methacrylates are preferred.

The thermally expandable microcapsule of the present invention comprises 55 to 65% by weight of polyacrylonitrile (I) and 10 to 20% by weight of polymethacrylonitrile (II) based on the whole thermally expandable microcapsule. It is preferable to contain 0.1 to 1.0% by weight of polymer (III) other than I) and polymethacrylonitrile (II).
In the present invention, by defining the content relative to the entire thermally expandable microcapsule, it becomes possible to define the effective amount of each component.

The preferable lower limit of the weight average molecular weight of the polymer constituting the shell is 100,000, and the preferable upper limit is 2,000,000. If it is less than 100,000, the strength of the shell may be reduced, and if it is more than 2,000,000, the strength of the shell may be too high, and the expansion ratio may be reduced.

The shell constituting the thermally expandable microcapsule has a degree of gelation of 80% or more.
When the degree of gelation is 80% or more, resistance to shearing at the time of molding can be maintained.
The degree of gelation is preferably 80 to 90%.
The degree of gelation can be measured by the DMF swelling method (implemented according to ASTM D2765 except that N, N-dimethylformamide is used as the solvent).

The above-mentioned shell may further contain a stabilizer, an ultraviolet absorber, an antioxidant, an antistatic agent, a flame retardant, a silane coupling agent, a coloring agent and the like, if necessary.

In the thermally expandable microcapsule of the present invention, a volatile expanding agent is included in the above-mentioned shell as a core agent. The volatile expanding agent is a substance which becomes gaseous at a temperature below the softening point of the polymer constituting the shell, and a low boiling point organic solvent is preferred.
In the thermally expandable microcapsule of the present invention, the volatile expanding agent (core agent) contains a hydrocarbon having 8 or more carbon atoms. By using such a hydrocarbon, it is possible to obtain a thermally expandable microcapsule which has a high expansion ratio in a high temperature range and is not easily stagnant (difficult to deform).
In addition, as a volatile expansion agent, a thermal decomposition type compound which is thermally decomposed to a gaseous state by heating may be used.

Examples of the above-mentioned hydrocarbon having 8 or more carbon atoms include isooctane, octane, decane, isododecane, dodecane, hexanedecane and the like.
These volatile expanding agents may be used alone or in combination of two or more.

As said core agent, volatile expansion agents other than the said C8 or more hydrocarbon may be included. Examples of such volatile expanding agents include ethane, ethylene, propane, propene, n-butane, isobutane, butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether and the like. Be In addition, chlorofluorocarbons such as CCl ₃ F, CCl ₂ F ₂ , CClF ₃ , CClF ₂ -CClF _{2 and the} like; tetraalkylsilanes such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-n-propylsilane, etc. Be Among these, isobutane, n-butane, n-pentane, isopentane, n-hexane and mixtures thereof are preferable. Two or more of these volatile expanding agents may be used in combination.
Moreover, you may use the thermal decomposition type compound which is thermally decomposed by heating and becomes gaseous as a volatile expansion agent.

In addition, in the thermally expandable microcapsule, the content of the core agent is 15 to 30% by weight. While being excellent in the durability to the shear at the time of shaping | molding by being in the said range, foaming ratio can be improved.

The lower limit of the maximum foaming temperature (Tmax) of the thermally expandable microcapsule of the present invention is 170 ° C. When the temperature is less than 170 ° C., the heat resistance is lowered, so that the thermally expandable microcapsules rupture and shrink in a high temperature region or at the time of molding and processing. In addition, during foaming of the masterbatch pellets, foaming occurs due to shearing, and unfoamed masterbatch pellets can not be stably produced. A more preferable lower limit is 180 ° C., and a preferable upper limit is 240 ° C.
In the present specification, when the diameter of the thermally expandable microcapsule is measured while heating the thermally expandable microcapsule from normal temperature, the maximum foaming temperature is when the diameter of the thermally expandable microcapsule is maximized (maximum displacement amount). Means temperature.

Moreover, the preferable upper limit of foaming start temperature (Ts) is 170 degreeC. If the temperature exceeds 170 ° C., particularly in the case of injection molding, the core back foam molding in which the mold is fully filled with the resin material and then the mold is desired to be foamed. May not go up. A preferred lower limit is 120 ° C., and a more preferred upper limit is 150 ° C.

The preferable lower limit of the volume average particle diameter of the thermally expandable microcapsule of the present invention is 5 μm, and the preferable upper limit is 100 μm. If the particle size is less than 5 μm, the resulting molded article may be too small in size, which may make the weight reduction of the molded product insufficient. If it exceeds 100 μm, the resulting molded article may have too large a cell size. Can be a problem in terms of A more preferable lower limit is 10 μm, and a more preferable upper limit is 45 μm.

The method for producing the thermally expandable microcapsule of the present invention is not particularly limited, but the following method can be used.
For example, the step of preparing an aqueous medium, an oily mixture containing acrylonitrile, methacrylonitrile, a monomer composition containing the above acrylonitrile and a monomer other than methacrylonitrile, and a volatile expanding agent is dispersed in an aqueous medium. It can manufacture by performing a process and a process of polymerizing the above-mentioned monomer.

When producing the thermally expandable microcapsules of the present invention, the process of preparing an aqueous medium is first carried out. Specifically, for example, an aqueous dispersion medium containing a dispersion stabilizer is prepared by adding water and a dispersion stabilizer and, if necessary, a co-stabilizer, to a polymerization reaction vessel. In addition, alkali metal nitrite, stannous chloride, stannic chloride, potassium dichromate and the like may be added, if necessary.

Examples of the dispersion stabilizer include silica, calcium phosphate, magnesium hydroxide, aluminum hydroxide, ferric hydroxide, barium sulfate, calcium sulfate, sodium sulfate, calcium oxalate, calcium carbonate, barium carbonate, magnesium carbonate and the like. It can be mentioned.

The addition amount of the dispersion stabilizer is not particularly limited and is appropriately determined depending on the type of dispersion stabilizer, the particle diameter of microcapsules, etc., but the preferable lower limit is 0.1 parts by weight, preferably 100 parts by weight of the monomer. The upper limit is 20 parts by weight.

Examples of the above-mentioned co-stabilizer include condensation products such as condensation products of diethanolamine and aliphatic dicarboxylic acid, and condensation products of urea and formaldehyde. Also, polyvinyl pyrrolidone, polyethylene oxide, polyethylene imine, tetramethyl ammonium hydroxide, gelatin, methyl cellulose, polyvinyl alcohol, dioctyl sulfosuccinate, sorbitan ester, various emulsifiers and the like can be mentioned.

The combination of the dispersion stabilizer and the co-stabilizer is not particularly limited. For example, a combination of colloidal silica and a condensation product, a combination of colloidal silica and a water-soluble nitrogen-containing compound, magnesium hydroxide or calcium phosphate The combination with an emulsifier etc. are mentioned. Among these, a combination of colloidal silica and a condensation product is preferred.
Furthermore, as the above-mentioned condensation product, a condensation product of diethanolamine and an aliphatic dicarboxylic acid is preferable, and in particular, a condensation product of diethanolamine and adipic acid and a condensation product of diethanolamine and itaconic acid are preferable.

Examples of the water-soluble nitrogen-containing compound include polydialkylaminoalkyl (meth) acrylates represented by polyvinyl pyrrolidone, polyethylene imine, polyoxyethylene alkylamine, polydimethylaminoethyl methacrylate and polydimethylaminoethyl acrylate. In addition, polydialkylaminoalkyl (meth) acrylamide represented by polydimethylaminopropyl acrylamide and polydimethylaminopropyl methacrylamide, polyacrylamide, polycationic acrylamide, polyamine sulfone, polyallylamine and the like can be mentioned. Among these, polyvinyl pyrrolidone is preferably used.

The addition amount of the colloidal silica is appropriately determined by the particle diameter of the thermally expandable microcapsule, but the preferable lower limit is 1 part by weight and the preferable upper limit is 20 parts by weight with respect to 100 parts by weight of the vinyl monomer. A more preferable lower limit is 2 parts by weight, and a still more preferable upper limit is 10 parts by weight. Further, the amount of the condensation product or the water-soluble nitrogen-containing compound is also appropriately determined by the particle diameter of the thermally expandable microcapsule, but a preferable lower limit is 0.05 parts by weight, a preferable upper limit with respect to 100 parts by weight of the monomer. Is 2 parts by weight.

In addition to the dispersion stabilizer and the co-stabilizer, inorganic salts such as sodium chloride and sodium sulfate may be further added. By adding an inorganic salt, a thermally expandable microcapsule having a more uniform particle shape can be obtained. The amount of the inorganic salt added is usually preferably 0 to 100 parts by weight with respect to 100 parts by weight of the monomer.

The aqueous dispersion medium containing the above dispersion stabilizer is prepared by blending the dispersion stabilizer and the co-stabilizer in deionized water, and the pH of the aqueous phase at this time is the kind of the dispersion stabilizer or the co-stabilizer used. It is decided appropriately by For example, when silica such as colloidal silica is used as a dispersion stabilizer, the polymerization is carried out in an acidic medium, and in order to make the aqueous medium acidic, an acid such as hydrochloric acid is added as needed to make the pH of the system 3 It is prepared to -4. On the other hand, when using magnesium hydroxide or calcium phosphate, they are polymerized in an alkaline medium.

Next, in the method of producing the thermally expandable microcapsule, an oil mixture containing an acrylonitrile, methacrylonitrile, a monomer composition containing a monomer other than acrylonitrile and methacrylonitrile, and a volatile expanding agent is used as an aqueous medium. The process of dispersing in is carried out. In this step, the monomer composition and the volatile expanding agent may be separately added to the aqueous dispersion medium to prepare an oily mixture in the aqueous dispersion medium, but usually, both are mixed in advance to form an oily mixture. Then add to the aqueous dispersion medium. At this time, the oily mixture and the aqueous dispersion medium are prepared in advance in separate containers, and are mixed while being stirred in another container to disperse the oily mixture in the aqueous dispersion medium, and then the polymerization reaction vessel is prepared. You may add.
Although a polymerization initiator is used to polymerize the above-mentioned monomer, the above-mentioned polymerization initiator may be added in advance to the above-mentioned oil mixture, and the aqueous dispersion medium and the oil mixture are contained in the polymerization reaction vessel. The mixture may be added after stirring and mixing.

In the above-mentioned monomer composition, in order to polymerize the above-mentioned monomer, a polymerization initiator is contained.
As the above-mentioned polymerization initiator, for example, dialkyl peroxide, diacyl peroxide, peroxy ester, peroxy dicarbonate, azo compound and the like are suitably used.
Specific examples thereof include dialkyl peroxides such as methyl ethyl peroxide, di-t-butyl peroxide and dicumyl peroxide; isobutyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5 And diacyl peroxides such as 5-trimethylhexanoyl peroxide.
Also, t-butylperoxypivalate, t-hexylperoxypivalate, t-butylperoxyneodecanoate, t-hexylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodeca Noate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate and the like.
Also, peroxy esters such as cumylperoxy neodecanoate, (α, α-bis-neodecanoylperoxy) diisopropylbenzene; bis (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propyl -Oxy dicarbonate, diisopropyl peroxy dicarbonate etc. are mentioned.
Further, peroxydicarbonates such as di (2-ethylethylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate and the like can be mentioned.
In addition, 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), Azo compounds such as 1,1′-azobis (1-cyclohexanecarbonitrile) and the like can be mentioned.
In the present invention, in order to preferentially polymerize acrylonitrile, it is preferable to use t-butyl peroxypivalate or 2,2'-azobisisobutyronitrile as a polymerization initiator. This makes it possible to increase the proportion of polyacrylonitrile having high plasticizer resistance compared to polymethacrylonitrile.

As a method of emulsifying and dispersing the above-mentioned oily mixed solution in an aqueous dispersion medium with a predetermined particle diameter, a method of stirring with a homomixer (for example, manufactured by Tokushu Kika Kogyo Co., Ltd.) or the like, And the like, and the like.
The stationary dispersion device may be separately supplied with an aqueous dispersion medium and a polymerizable mixture, or may be supplied with a dispersion mixed and stirred in advance.

The thermally expandable microcapsule of the present invention can be produced, for example, by carrying out the step of polymerizing a monomer by heating the dispersion obtained through the above-described steps. The thermally expandable microcapsules produced by such a method have a high maximum foaming temperature, are excellent in heat resistance, and do not rupture or shrink even in a high temperature region or during molding processing. In addition, since the heat resistance is high, unfoamed master batch pellets can be stably produced without being foamed by shear at the time of master batch pellet production.

A molding resin composition containing the thermally expandable microcapsule of the present invention, a vinyl chloride resin and a plasticizer is also one of the present invention.
Such a resin composition for molding has durability against strong shear at the time of molding, makes it possible to produce a foamed molded product having a high expansion ratio and an excellent appearance that is not easily yellowed.

The molding resin composition of the present invention contains a vinyl chloride resin.
As the above vinyl chloride resin, in addition to a vinyl chloride homopolymer, a copolymer of a monomer having an unsaturated bond copolymerizable with a vinyl chloride monomer and a vinyl chloride monomer, and a polymer obtained by graft copolymerizing a vinyl chloride monomer A graft copolymer etc. can be used. These polymers may be used alone or in combination of two or more.

Examples of the monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer include α-olefins, vinyl esters, vinyl ethers, (meth) acrylic esters, aromatic vinyls, halogenated vinyl vinyls, and the like. N-substituted maleimides etc. are mentioned and 1 type (s) or 2 or more types of these are used.
Examples of the α-olefins include ethylene, propylene and butylene. Examples of the vinyl esters include vinyl acetate and vinyl propionate. Examples of the vinyl ethers include butyl vinyl ether and cetyl vinyl ether. Be
Also, examples of the (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, butyl acrylate, phenyl methacrylate and the like, and examples of the aromatic vinyls include styrene, α-methylstyrene and the like Can be mentioned.
Furthermore, examples of the halogenated vinyl vinyls include vinylidene chloride and vinylidene fluoride, and examples of the N-substituted maleimides include N-phenyl maleimide and N-cyclohexyl maleimide.
Among them, ethylene and vinyl acetate are preferable.

The polymer for graft copolymerization of vinyl chloride is not particularly limited as long as it graft-polymerizes vinyl chloride. As such a polymer, for example, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate-carbon monoxide copolymer, Ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, etc. are mentioned. Moreover, an acrylonitrile butadiene copolymer, a polyurethane, a chlorinated polyethylene, a chlorinated polypropylene etc. are mentioned, These may be used independently and 2 or more types may be used together.
The vinyl chloride may be graft copolymerized with the acrylic resin emulsion rubber.
The polymerization method of the above-mentioned PVC is not particularly limited, and conventionally known water suspension polymerization, bulk polymerization, solution polymerization, emulsion polymerization and the like can be used.

It is preferable that the polymerization degree of the said vinyl chloride resin is 600-1200. By setting it in the said range, it can be set as the product which satisfies both fluidity and product strength. The more preferable lower limit of the degree of polymerization of the vinyl chloride resin is 800, and the more preferable upper limit is 1,000.

In the resin composition for molding of the present invention, the content of the vinyl chloride resin is preferably 40 parts by mass with a preferable lower limit and 60 parts by mass with a preferable upper limit with respect to 100 parts by mass of the resin composition for molding. By adding the vinyl chloride resin in this range, it is possible to maintain a good appearance of the molded body while maintaining the physical properties.
The more preferable lower limit of the content of the vinyl chloride resin is 45 parts by mass, and the more preferable upper limit is 55 parts by mass.

The molding resin composition of the present invention contains a plasticizer.
Examples of the plasticizer include phthalic acid esters such as polypropylene glycol, dioctyl phthalate, dibutyl phthalate, butyl benzyl phthalate, and the like. Dioctyl adipate, isodecyl succinate, aliphatic carbonic acid such as dibutyl sebacate, butyl oleate and the like An acid ester etc. are mentioned. In addition, glycol esters such as pentaerythritol ester, phosphoric esters such as trioctyl phosphate and tricresyl phosphate, epoxy plasticizers such as epoxidized soybean oil and benzyl epoxy stearate, chlorinated paraffin and the like can be mentioned. These plasticizers may be used alone or in combination of two or more.

The content of the plasticizer in the molding resin composition of the present invention is not particularly limited, but the lower limit is 60 parts by weight and the preferable upper limit is 80 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. When the content of the above-mentioned plasticizer is within this range, the shaping property can be exhibited, and the plasticizer does not bleed out from the foam molded article. A more preferable lower limit of the content of the plasticizer is 65 parts by weight, and a more preferable upper limit is 75 parts by weight.

The ratio of the plasticizer content in the molding resin composition of the present invention to the polyacrylonitrile content of the shell constituting the thermally expandable microcapsule (plasticizer content / polyacrylonitrile content) is 35 or less Is preferred. By setting the ratio to 35 or less, the specific gravity can be lowered even when the thermally expandable microcapsules come in contact with the plasticizer at a relatively low temperature (150 ° C. or less). A more preferable upper limit of the above ratio is 34, and a preferable lower limit is 25.

The molding resin composition of the present invention may contain, if necessary, additives such as lubricants, processing aids, heat resistance improvers, UV absorbers, heat stabilizers, light stabilizers, fillers, thermoplastic elastomers, and pigments. It may be mixed.

The molded resin composition of the present invention is molded using a known molding method, and the above-mentioned thermally expandable microcapsule is foamed by heating at the time of molding, whereby a foamed molded article can be produced. Such a foam is also one of the present invention.
The foam molded article of the present invention obtained by such a method has high appearance quality, uniform closed cell formation, and is excellent in lightness, heat insulation, impact resistance, rigidity, etc. It can be suitably used for applications such as building materials, automobile parts, shoe soles and the like.

In addition, the molding resin composition of the present invention may be used as a masterbatch pellet.
The method for producing the masterbatch pellets is not particularly limited, and for example, raw materials such as a matrix resin such as a vinyl chloride resin and various additives are previously kneaded using a co-directional twin screw extruder or the like. Then, the method is heated to a predetermined temperature, and the molding resin composition of the present invention is cut into a desired size by a pelletizer to form pellets into master batch pellets.
Moreover, you may manufacture the masterbatch pellet of pellet shape by granulating the resin composition for shaping | molding of this invention with a granulator.
The kneader is not particularly limited as long as it can knead the thermally expandable microcapsule without breaking it, and examples thereof include a pressure kneader and a Banbury mixer.

It does not specifically limit as a shaping | molding method of the foaming molding of this invention, For example, kneading | mixing molding, calendar molding, extrusion molding, injection molding etc. are mentioned. In the case of injection molding, the method of construction is not particularly limited. A short circuit method in which a resin material is partially put in a mold for foaming, or a core back method in which the mold is fully foamed after full filling with the resin material. Etc.

ADVANTAGE OF THE INVENTION According to this invention, it can be set as the resin composition for shaping | molding which can be used suitably also to kneading | mixing shaping | molding to which a strong shear force is added, a calendaring shaping | molding, extrusion molding, injection molding etc. In addition, a foam molded product having a high foaming ratio and having desired foaming characteristics can be obtained. Furthermore, the resulting foam molded article can be excellent in appearance and difficult to yellow.

EXAMPLES The embodiments of the present invention will be described in more detail by way of the following examples, but the present invention is not limited to these examples.

Example 1
(Preparation of thermally expandable microcapsules)
After 130 g of colloidal silica having a solid content of 20% by weight, 4.6 g of polyvinylpyrrolidone and 480 g of sodium chloride were added to 1,500 g of ion exchanged water and mixed, the pH was adjusted to 3.5 to prepare an aqueous dispersion medium.
Acrylonitrile 405 g (54.59 parts by weight), methacrylonitrile 157 g (21.15 parts by weight), methyl methacrylate 0.6 g (0.08 parts by weight), trimethylolpropane triacrylate 2.2 g (0.3 parts by weight) ) Were mixed to obtain a homogeneous solution monomer composition. Therein, 4.5 g of 2,2'-azobis (isobutyronitrile), 4.5 g of 2,2'-azobis (2,4-dimethyl valeronitrile), 84.93 g (11.46 parts by weight) of normal pentane, 21.27 g (2.87 parts by weight) of isopentane and 70.8 g (9.55 parts by weight) of isooctane were added and mixed in an autoclave. In addition, weight part prescription represents the quantity at the time of making the sum total of a monomer composition and a volatile expansion agent into 100 weight part.
Thereafter, the aqueous dispersion medium was charged in an autoclave, stirred at 1,000 rpm for 10 minutes, purged with nitrogen, reacted at a reaction temperature of 60 ° C. for 10 hours, and reacted at 80 ° C. for 2 hours. The reaction pressure was 0.5 MPa, and the stirring was performed at 200 rpm. The obtained polymer slurry was predewatered with a dehydrator (centre) and then dried to obtain thermally expandable microcapsules.

(Production of resin composition for molding, foamed molded product)
20 parts by weight of heavy calcium carbonate (Whiteton 305, manufactured by Shiroishi Kogyo Co., Ltd.) as a filler and 100 parts by weight of a vinyl chloride resin, and a tin-based stabilizer (ONZ142AF, manufactured by Sankyo Kaisha, Ltd.) 3.5 as a heat stabilizer Parts by weight and 1 part by weight of polyethylene wax (AC 316A, manufactured by Honeywell) as a processing aid were added and mixed. After heating to 100 ° C., 75 parts by weight of dioctyl phthalate was added as a plasticizer and mixed while maintaining 100 ° C. Thereafter, the resultant was cooled to 70 ° C., and 4 parts by weight of the obtained thermally expandable microcapsule was added to obtain a molding resin composition.
The obtained molding resin composition was wound on two rolls at a temperature of 95 to 105 ° C. and a rotation number of 10 rpm, and then kneaded for 3 minutes and 6 minutes to obtain roll products.
Subsequently, the roll product was put into a 150 mm square mold having a thickness of 2 mm, preheated for 3 minutes at a pressure of 2 MPa and a temperature of 100 ° C., pressed for 1 minute, and then cooled for 2 minutes to obtain a pressed product.
The pressed product (150 mm square) was divided into 16 equal parts, placed in a hot air oven set at 180 ° C., and heated for 4 minutes and 6 minutes to obtain a foam-molded article.

(Examples 2 to 3, Comparative Examples 1 to 3)
Acrylonitrile, methacrylonitrile, methacrylic acid, methyl methacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol dimethacrylate, and volatile expander were mixed according to the composition shown in Table 1 Thermally expandable microcapsules were obtained in the same manner as in Example 1 except for the above. Similarly, a molding resin composition and a foam were obtained.

(Evaluation method)
The performance of the obtained thermally expandable microcapsules and the foamed molded product was evaluated by the following method. The results are shown in Table 2.

(1) Evaluation of Thermally Expandable Microcapsule (1-1) Compositional Analysis of Core / Shell 0.1 mg of the thermally expandable microcapsule obtained was subjected to thermal decomposition GC / MS using the shell component and the core component under the following conditions The composition ratio of In Table 2, PAN represents polyacrylonitrile, PMAN represents polymethacrylonitrile, and PMMA represents polymethyl methacrylate.
Furthermore, the component ratio of polymethacrylic acid (PMAA) was measured by reaction pyrolysis GC / MS using tetramethylammonium hydroxide for 0.2 mg of sample.
In addition, thermal decomposition GC / MS measurement conditions and reaction thermal decomposition GC / MS are as follows.

<Conditions for thermal decomposition GC / MS measurement>
Thermal decomposition temperature: 550 ° C (FRONTIER LAB PY-2020D)
GC / MS system: Jms-Q1000 GC K9 (manufactured by Nippon Denshi Co., Ltd.)
Inlet temperature: 300 ° C
Column: Ultra-ALLO-1 (non-polar) 0.25 mm φ × 30 m × 0.25 μm
He flow rate: 1.0 mL / min (split ratio 1: 50)
Column temperature: 40 ° C (3 min) → 10 ° C / min → 300 ° C (5 min)
MS measurement range: 35-600 amu
MS temperature: ion source: 230 ° C., interface: 250 ° C.

<Reaction pyrolysis GC / MS measurement conditions>
Thermal decomposition temperature: 300 ° C (PY-2020D, manufactured by FRONTIER LAB)
GC / MS device: JMS-Q1000 GC K9 (manufactured by Nippon Denshi Co., Ltd.)
Inlet temperature: 300 ° C
Column: Ultra-ALLO-1 (non-polar) 0.25 mm φ × 30 m × 0.25 μm
He flow rate: 1.0 mL / min (split ratio 1: 50)
Column temperature: 40 ° C (3 min) → 10 ° C / min → 300 ° C (5 min)
Ionization voltage: 70 eV
MS measurement range: 35-600 amu
MS temperature: ion source; 230 ° C., interface: 250 ° C.
Reaction reagent: tetramethyl ammonium hydroxide

(1-2) Volume Average Particle Size Particle Size Distribution The volume average particle size was measured using a particle size analyzer (LA-950, manufactured by HORIBA).

(1-3) Foaming start temperature, maximum foaming temperature The foaming start temperature (Ts) and the maximum foaming temperature (Tmax) were measured using a thermal mechanical analyzer (TMA) (TMA 2940, manufactured by TA instruments). Specifically, 25 μg of sample is placed in an aluminum container with a diameter of 7 mm and a depth of 1 mm, and heated from 80 ° C. to 250 ° C. at a heating rate of 5 ° C./min. The displacement in the vertical direction of the measurement terminal was measured, and the temperature at which the displacement started to rise was taken as the foaming start temperature. Further, the expansion ratio was measured, and the temperature at which the expansion ratio became maximum was taken as the maximum expansion temperature.

(1-4) Degree of Gelation The degree of gelation was measured by a method in accordance with ASTM D2765 except that N, N-dimethylformamide was used as a solvent.

(2) Evaluation of Foamed Molded Product (2-1) Measurement of Density The density of the obtained molded product was measured by a method according to JIS K-7112 A method (substitution method in water).

(2-2) Yellowness (YI)
The yellowness of the surface of the molded article (6 minutes for roll, 4 minutes for heating) was measured using a color difference meter (NR-3000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) to obtain a YI value.

According to the present invention, thermally expandable microcapsules capable of producing a foam molded article having an excellent appearance that is resistant to strong shear during molding, has a high foaming ratio, and is resistant to yellowing, It is possible to provide a molding resin composition and a foamed molded article using thermally expandable microcapsules.

Claims (3)

3 to 6 parts by weight of a thermally expandable microcapsule and 60 to 80 parts by weight of a plasticizer based on 100 parts by weight of a vinyl chloride resin ,
In the thermally expandable microcapsule, a volatile expansive agent is included as a core agent in a shell made of a polymer, and a thermally expandable microparticle having a maximum foaming temperature of 170 ° C. or more and 15 to 30 wt% of the core agent A capsule, the shell comprising 70 to 90% by weight of polyacrylonitrile (I), 9.9 to 29.9% by weight of polymethacrylonitrile (II), the polyacrylonitrile (I) and polymethacrylonitrile ( II) containing 0.01 to 3.0% by weight of the polymer (III) other than II, having a degree of gelation of 80% or more, and the core agent containing a hydrocarbon having a carbon number of 8 or more forming form the resin composition for you, characterized in that. The ratio of the plasticizer content in the molding resin composition to the polyacrylonitrile content of the shell constituting the thermally expandable microcapsule (plasticizer content / polyacrylonitrile content) is 35 or less. The molding resin composition according to claim 1 . A foamed molded article comprising the resin composition for molding according to claim 1 or 2 .