JPH0333745B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is a sheet molding compound that exhibits excellent performance in compound viscosity characteristics before curing, surface characteristics (surface smoothness, surface gloss), and impact resistance of molded products after curing. The present invention relates to unsaturated polyester resin compositions that can be used as bulk molding compounds (SMC) or bulk molding compounds (BMC). (Prior Art and its Problems) In recent years, as the movement toward weight reduction of automobiles has become more active, attempts have been made to use unsaturated polyester resins for outer panel parts and structural parts of automobiles. In general, molded products using unsaturated polyester resins have a mold shrinkage rate of 4 to 12% during curing, so thermoplastic resins such as polystyrene, polymethyl methacrylate, and polyvinyl acetate are usually used. It is formulated as a "low shrinkage agent". However, even in this case, phase separation may occur between the unsaturated polyester resin and the low-shrinkage agent after compounding, and warping or warping may occur even if the molded product is formed.
Currently, undesirable surface characteristics such as waviness are still induced. Therefore, in unsaturated polyester resin compositions, in addition to improving impact resistance, there is a tendency to emphasize these surface properties and thickening properties after compounding, and improving them has become an important issue. There is. For this reason, many attempts to improve these properties have been proposed. For example, JP-A-48-34289 and JP-A-49-30480 propose a method of adding a styrene-butadiene block copolymer. has been done. However, in these methods, the added styrene-butadiene block copolymer component and unsaturated polyester resin component undergo phase separation after compounding, resulting in a cured product with poor surface properties and impact resistance. This is the actual situation. In an attempt to improve this drawback, JP-A-52-
No. 148588 and Japanese Unexamined Patent Publication No. 130653/1988 propose a method of adding a styrene-butadiene block copolymer containing a carboxyl group or a salt thereof at the end of the molecular chain. However, even with these methods, the problem of phase separation between the rubber component and the unsaturated polyester component cannot be essentially solved, and the reality is that the surface properties and impact resistance have not been improved. Under these circumstances, furthermore,
Attempts to improve this drawback have been proposed in JP-A-56-115309 and JP-A-56-115310. It is characterized by the addition of a modified block copolymer to which groups are bonded. Furthermore, for the same purpose, JP-A-58-8718 discloses that a molecular unit containing a carboxylic acid group or its derivative group is added to a hydrogenated block copolymer obtained by hydrogenating a styrene-butadiene block copolymer. A method has been proposed in which a modified block copolymer with which is bonded is added.
However, although the above-mentioned problem of phase separation after compounding with the unsaturated polyester component has been improved by using these modified block copolymers, the surface properties of the cured products obtained are still insufficient, and further manufacturing From the above viewpoints, the handling viscosity was too high and the thickening properties were still insufficient. (Means for Solving the Problems) The present invention was made to solve the above-mentioned problems under the conventional technology, and by using specific components, surface smoothness, surface gloss, and size can be improved. It has been discovered that a cured composition of an unsaturated polyester resin composition with excellent stability can be obtained, and it has also been discovered that the composition is a practically useful composition. That is, the present invention provides: (a) an unsaturated polyester resin; (b) a molecular unit consisting of the following components (i) and (ii), one of which contains a carboxylic acid group or a derivative group thereof; (i) a polymer block A mainly composed of at least one vinyl aromatic compound;
A block copolymer consisting of a polymer block B mainly composed of a conjugated diene compound is hydrogenated to hydrogenate at least 80% of the aliphatic double bonds based on the conjugated diene compound in the copolymer. Hydrogenated block copolymer (ii) A polymer block A mainly composed of at least one vinyl aromatic compound and at least one
A block copolymer consisting of a polymer block B mainly composed of a conjugated diene compound (c) a vinyl monomer (d) a curing agent. This is what we provide. The present invention will be described in detail below. The unsaturated polyester resin used as component (a) in the present invention is obtained by a condensation reaction between an α,β-unsaturated dibasic acid or a mixture of this and a saturated dibasic acid and a polyhydric alcohol. . Examples of the dibasic acid component include maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, chlorinated maleic acid, glutaconic acid, and acid anhydrides thereof. In addition, saturated dibasic acids include phthalic acid, halogenated phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hettic acid, endomethylenetetrahydrophthalic acid, succinic acid, adipic acid, glutaric acid, sebacic acid,
Mention may be made of pimelic acid or these acid anhydrides. Further, if necessary, monobasic acids such as acrylic acid and methacrylic acid, and polybasic acids such as trimellitic acid, hemimelittic acid and trimesic acid can be used in combination with the above-mentioned dibasic acids as a modifying agent. Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,
3-butanediol, tetramethylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, bisphenol A
Examples include ethylene oxide and/or propylene oxide adducts. Further, if necessary, higher aliphatic alcohols such as amyl alcohol, hexyl alcohol, pentyl alcohol, octyl alcohol, etc., monohydric alcohols such as tetrahydrofurfuryl alcohol, polyhydric alcohols such as glycerin, pentaerythritol, trimethylolethane, sorbitol, etc. It can also be used in combination with alcohol. Next, component (i) shown as component (b) of the present invention is:
A block copolymer (hereinafter referred to as component ,
A product obtained by hydrogenating at least 80% of the aliphatic double bonds based on the conjugated diene compound in the copolymer (hereinafter abbreviated as hydrogenated block copolymer) ). Here, the block copolymer shown as component (ii) is, for example, A-B, A-B-A, B-A-B-
It is a vinyl aromatic compound-conjugated diene compound block copolymer having a structure such as A, (A-B) _-4Si , A-B-A-B-A. This block copolymer contains 5 to 60% by weight, preferably 10 to 40% by weight of a vinyl aromatic compound.Moreover, referring to the block structure, polymer block A mainly composed of vinyl aromatic compounds is It has a structure of a compound polymer block or a copolymer block of a vinyl aromatic compound and a conjugated diene compound containing more than 50% by weight and preferably 70% by weight or more of a vinyl aromatic compound, and furthermore, a conjugated diene compound. Polymer block B mainly composed of a diene compound is a conjugated diene compound polymer block, or a copolymer of a conjugated diene compound and a vinyl aromatic compound containing more than 50% by weight and preferably 70% by weight or more of a conjugated diene compound. It has a block structure. Furthermore, polymer block A mainly composed of vinyl aromatic compounds and polymer block B mainly composed of conjugated diene compounds are based on the distribution of conjugated diene compounds or vinyl aromatic compounds in the molecular chains of each polymer block. may be random, tapered (monomer component increases or decreases along the molecular chain), partially block-like, or any combination thereof, and polymer blocks mainly composed of vinyl aromatic compounds and When there are two or more polymer blocks each containing a conjugated diene compound as a main component, each block may have the same structure or may have a different structure. As the vinyl aromatic compound constituting the block copolymer, one or more compounds are selected from, for example, styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, and the like, with styrene being preferred. In addition, examples of the conjugated diene compounds constituting the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene,
One or more types are selected from 2,3-dimethyl-1,3-butadiene and the like, and among them, butadiene, isoprene, and a combination thereof are preferred. In a polymer block mainly composed of a conjugated diene compound, the microstructure within the block can be arbitrarily selected. For example, in a polybutadiene block, the 1,2-microstructure is 10
~80%, preferably 10-65%. The number average molecular weight of the block copolymer is 5000~
The range is 1,000,000, preferably 10,000 to 800,000, more preferably 30,000 to 300,000, and the molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) is 10 or less. The molecular structure of the block copolymer provided in the present invention may be linear, branched, radial, or any combination thereof, and any production method may be used as long as it has the above-mentioned structure. It doesn't matter if it's something you can get. For example, by the method described in Japanese Patent Publication No. 40-23798, a vinyl aromatic compound-conjugated diene compound block copolymer is synthesized in an inert solvent using a lithium catalyst, etc., and the (ii) component of the present invention is synthesized. It can be provided as a block copolymer of The hydrogenated block copolymer used as component (i) of the present invention may be any type of block copolymer that meets the requirements for the block copolymer shown as component (ii) above. It can be used as a block copolymer. This block copolymer before hydrogenation is prepared by the method described in, for example, Japanese Patent Publication No. 42-8704 or Japanese Patent Application Laid-Open No. 59-133203.
It can be synthesized by hydrogenation in an inert solvent in the presence of a hydrogenation catalyst, and can be made into a hydrogenated block copolymer shown as component (i) of the present invention. In this case, at least 80% of the aliphatic double bonds based on the conjugated diene compound of the vinyl aromatic compound-conjugated diene compound block copolymer are hydrogenated, and the polymer block mainly composed of the conjugated diene compound is formed into an olefinic compound in morphology. Polymer block B
can be converted to . In addition, regarding the hydrogenation rate of aromatic double bonds based on the vinyl aromatic compound copolymerized into block A mainly consisting of a vinyl aromatic compound and, if necessary, polymer block B mainly consisting of a conjugated diene compound. Although there is no particular restriction, it is preferable that the hydrogenation rate be 20% or less. The amount of unhydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be measured using an infrared spectrophotometer,
This can be easily determined using a nuclear magnetic resonance apparatus or the like. Component (b) of the present invention consists of the above-mentioned components (i) and (ii), and it is essential that one of them is a modified polymer bonded with a molecular unit containing a carboxylic acid group or a derivative group thereof. be. Here, the modified polymer of component (i) (hereinafter simply abbreviated as modified hydrogenated block copolymer) refers to the hydrogenated block copolymer (i) having the above-mentioned structure and α,
A product obtained by a graft reaction with a β-unsaturated carboxylic acid or its anhydride, ester, etc. (hereinafter abbreviated as α,β-unsaturated carboxylic acids) in the presence or absence of an organic peroxide. may be in either a molten state or a solution state. In addition, the modified hydrogenated block copolymer is a hydrogenated block copolymer.
Those to which 0.05 to 10 parts by weight of α,β unsaturated carboxylic acids are added per 100 parts by weight can be used as component (b) of the present invention. Addition amounts other than this do not give favorable results regarding the thickening properties and phase separation of the resulting unsaturated polyester resin composition after compounding. This gives a compound with a much higher viscosity than the viscosity at the time of molding, making it difficult to mold, which is undesirable. Therefore, addition amounts outside these ranges are not preferable because the resulting cured product will have non-uniformity in surface characteristics and physical properties. Here, examples of α,β-unsaturated carboxylic acids that can be provided during the grafting reaction include maleic acid, maleic anhydride, fumaric acid, itaconic acid, acrylic acid, acrylic ester, crotonic acid, cis-4 -cyclohexene-1,2-dicarboxylic acid and its anhydride, endo-cis-bicyclo[2,2,1]-5-heptene-2,3-dicarboxylic acid and its anhydride, maleimide, etc. Among these, maleic anhydride is preferred. Examples of organic peroxides that can be used include dicumyl peroxide, di-tert-
Butyl peroxide, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,
5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, n-butyl 4,4-bis(tert-butylperoxy)valerate, 1,1
-bis(tert-butylperoxy)3,3,5-
Examples include trimethylcyclohexane and the like, and a suitable one can be selected from these. The method for producing the modified hydrogenated block copolymer is not particularly limited in the present invention, but the modified hydrogenated block copolymer obtained may have a structure deviating from the above-mentioned characteristics, or may have a structure such as a gel. Production methods that include undesirable components or that significantly increase the melt viscosity and deteriorate processability are not preferred. As an example of a preferred manufacturing method, for example, in an extruder, 150~
hydrogenated block copolymer as described above at a temperature of 350°C;
There is a method in which α,β-unsaturated carboxylic acids and, if necessary, an organic peroxide are melt-kneaded and radical-modified. The obtained modified hydrogenated block copolymer may be ionomerized with a monovalent or higher valent metal ion. Furthermore, in the modified hydrogenated block copolymer thus obtained, unreacted α,β-unsaturated carboxylic acids or derivatives thereof generally remain as unreacted substances; The object may be removed completely or left in place. Next, the modified polymer (hereinafter simply referred to as modified block copolymer) as component (ii) refers to block copolymer (ii) having the above-mentioned structure and α,β-unsaturated carboxylic acid or its anhydride. It is obtained by grafting compounds, esters, etc. (hereinafter abbreviated as α,β-unsaturated carboxylic acids) in a molten state or a solution state, with or without using a radical initiator. The production method is not particularly limited in the present invention, but methods may be used in which the obtained modified block copolymer contains undesirable components such as gel, or in which the flowability is reduced and processability is deteriorated. This is not preferable, and it is preferable to carry out the modification reaction in an extruder or the like by adding additives such as antioxidants and under melt-mixing conditions that substantially do not generate radicals. The modified block copolymer that can be provided in the present invention is one in which 0.05 to 10 parts by weight of α,β-unsaturated carboxylic acids are added per 100 parts by weight of the block copolymer. Addition amounts other than this will not give favorable results regarding the thickening properties and phase separation of the resulting unsaturated polyester resin composition after compounding. This gives a compound with a much higher viscosity than the viscosity at the time of molding, making it difficult to mold, which is undesirable. Therefore, addition amounts outside these ranges are not preferable because the resulting cured product will have non-uniformity in surface characteristics and physical properties. Here, as the α,β-unsaturated carboxylic acids that can be used in the grafting reaction of the block copolymer, the α,β-unsaturated carboxylic acids used in the graft modification reaction of the hydrogenated block copolymer described above It can be arbitrarily selected from carboxylic acids, and among these, maleic anhydride is preferred. The obtained modified block copolymer may be ionomerized with a monovalent or higher valent metal ion, and further,
Unreacted α,β-unsaturated carboxylic acids may remain unreacted in the modified block copolymer or may be completely removed. Therefore, the low shrinkage agent represented by component (b) of the present invention is composed of the modified polymer (modified hydrogenated block copolymer) of component (i) and the block copolymer of component (ii) described above. A low-shrinkage agent or a low-shrinkage agent consisting of a hydrogenated block copolymer as component (i) and a modified polymer (modified block copolymer) as component (ii) is provided. The vinyl monomer used as component (c) in the present invention acts as a crosslinking component. Examples of vinyl monomers include styrene, various substituted products of styrene, such as α-methylstyrene, vinyltoluene, dimethylstyrene, trimethylstyrene, halogenated styrene, tert-butylstyrene, styrene sulfonate, aminostyrene, Vinyl aromatic compounds such as p-benzylstyrene and p-phenoxystyrene, acrylic acid or methacrylic acid and methyl alcohol, ethyl alcohol, propyl alcohol, octyl alcohol, hexanol, tetrahydrofurfuryl alcohol, ethylene glycol, propylene glycol, etc. esters with aliphatic alcohols such as acrylic acid or methacrylic acid derivatives such as 2-aminoethyl-methacrylate, N,N-diethylamino-acrylate, N,N-diethylamino-methacrylate, maleic acid, fumaric acid, crotonic acid, itacon α,β-unsaturated dicarboxylic acids such as acids or their acid anhydrides, esters, amides, imides, etc., fumaric acid esters such as diethyl- and dioctyl fumarate, as well as various vinyl and vinylidene monomers, such as acrylonitrile. , methacrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, vinylene carbonate, vinyl-2
-chloroethyl ether, _C8 - _C18 alkyl vinyl ether, vinyl ester of _C8 - _C18 fatty acid, 2-vinylfuran, vinylphenol, vinylphenyldisiloxane, 2-vinylpyridine,
4-vinylpyridine, vinylpyrrole, vinylpyrrolidone, vinylsulfonic acid, vinylurethane,
Examples include methylvinylketone-2-vinylquinoline and vinylcarbazole. Also, 1,3
- Conjugated diene compounds such as butadiene, isobrene, piperylene, methylpentadiene, chloroprene, and 2-methoxybutadiene and 1
Alkoxy- and cyano derivatives of conjugated dienes such as -cyanobutadiene can also be used. moreover,
Polyfunctional crosslinkable vinyl monomers such as diallyl maleate, diallyl phthalate, divinylbenzene, divinyl ether, neopentyl glycol diacrylate, diallyl cyanurate, triallyl cyanurate, diallylphenyl phosphate, 2,3-divinylpyridine , divinylsulfone, 2,5-divinyl-6-methylpyridine, etc. can also be used. Preferred examples of these vinyl monomers include:
Examples include styrene, vinyltoluene, α-methylstyrene, chlorostyrene, divinylbenzene, methyl methacrylate, methyl acrylate, diallyl phthalate, and triallyl cyanurate. The curing agent as component (d) used in the present invention is:
Organic peroxides, organic hydroperoxides and azo compounds can be used. Some peroxides useful in this invention include dialkyl peroxides and diacyl peroxides. Alkyl peroxide has the general structure R-OO-
R', where R and R' are the same or different primary, secondary or tertiary alkyl, cycloalkyl, aralkyl or heterocyclic groups. Groups of peroxides suitable for use in the present invention include dicumyl peroxide, di-tert-butyl peroxide, tert-butylcumyl peroxide and 2,5-dimethyl-2,5-bis(tert-butyl peroxide). Contains oxy)hexane. Diacyl peroxide has the general structure RO(O)
OOO(O)R', in which R and R' are the same or different alkyl groups, cycloalkyl groups,
It is an aralkyl group, an aryl group or a heterocyclic group. Examples of some diacyl peroxides suitable for use in the present invention include dilauroyl peroxide, dibenzoyl peroxide, dicetyl peroxide, didecanoyl peroxide, di-(2,4-dichlorobenzoyl) peroxide, There are diisononanoyl peroxide and 2-methylpentanoyl peroxide. Additionally, peroxides useful in the present invention include methyl ethyl ketone peroxide, cyclohexanone peroxide, and the like, as well as particularly preferred peresters such as tert-butyl peroctoate and tert-butyl perpenzoate. Examples of hydroperoxides suitable for use in the present invention include tert-butyl hydroperoxide, cumyl hydroperoxide, 2,5
-dimethyl-2,5-dihydroperoxyhexane, p-methane hydroperoxide and diisopropylbenzene hydroperoxide. Examples of azo compounds that can be used in the present invention include diazoaminobenzene, N,N'-dichloroazodicarboxylic acid amide, azodicarboxylic acid diethyl ester, 1-cyano-1-(tert-butylazo)cyclohexanone, and azobis(iso butyronitrile). The blending ratio of each component constituting the composition of the present invention is 10 to 90 parts by weight, preferably 20 to 80 parts by weight of component (a) to 100 parts by weight of the total amount of components (a) to (c), More preferably, it is 20 to 60 parts by weight. Component (b) is a low shrinkage agent consisting of a modified polymer of component (i) and a modified polymer of component (ii), or a low shrinkage agent consisting of a modified polymer of component (i) and component (ii). Even in the case of the agent, the total amount can suitably be used in the range of 2 to 70 parts by weight, preferably 5 to 50 parts by weight, and furthermore, in the combination of each of the above-mentioned low shrinkage agents, the former component/the latter component = 0.11
It is necessary to satisfy the condition of ~9 (weight ratio).
If this ratio is less than 0.11, the initial viscosity of the compound will be low, the fluidity properties during heating will be high, and the glass fibers will be unevenly dispersed, making it impossible to obtain a homogeneous molded product. On the other hand, if this ratio exceeds 9,
If the initial viscosity of the compound becomes too high, excessive shearing may occur during kneading, which is undesirable and may cause the glass fibers to break, or the surface of the glass fibers may become insufficiently wetted during the filler or coating impregnation process. It is not possible to obtain molded products with improved properties. Therefore, it is necessary to keep this ratio within the above range, which results in a compound viscosity of 40 to 60 at BMC.
An unsaturated polyester resin composition with excellent surface properties (surface smoothness, surface gloss), dimensional stability, and impact resistance when molded under conditions of around 10,000 poise, or around 100,000 to 300,000 poise for SMC. yields a cured product. Next, component (c) is 10 to 80 parts by weight, preferably 20 to 80 parts by weight.
In the range of 70 parts by weight. In addition, the amount of curing agent (d) used in the present invention is (a) to (c)
0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, more preferably 0.5 to 5 parts by weight, based on a total of 100 parts by weight of the components.
It is 3 parts by weight. Other additives such as thickeners, fiber reinforcing agents, inorganic fillers, low shrinkage agents, pigments, colorants, lubricants, mold release agents, etc. may be added to the composition of the present invention as necessary. Can be done. The thickeners used in the invention are selected from the oxides and/or Mizuki oxides of metals of group of the periodic table, such as the oxides and hydroxides of magnesium, calcium, strontium, barium and zinc. Preferred are magnesium and/or calcium oxides or hydroxides. The above-mentioned thickener is used in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on a total of 100 parts by weight of components (a), (b), and (c) of the composition of the present invention. used. The fiber reinforcing agent used in the present invention includes glass, metal,
Silicate, asbestos, cellulose, carbon, graphite, polyester, polyacrylic, polyamide,
Selected from fibers such as polyolefin. Preferred is glass fiber. The above fiber reinforcing agent comprises component (a) of the composition of the present invention,
5 to 300 parts per 100 parts by weight of component (b) and component (c)
The amount used is preferably 20 to 200 parts by weight, more preferably 20 to 100 parts by weight. The filler used in the present invention is preferably an inorganic particulate filler, such as calcium carbonate, calcium silicate, silica, calcined clay, chalk, talc, limestone, anhydrous calcium sulfate, barium sulfate, asbestos,
Selected from powdered glass, quartz, aluminum hydrate, aluminum oxide, antimony oxide, etc. The above filler is component (a) of the composition of the present invention, and (b)
It is used in an amount of 50 to 800 parts by weight, preferably 100 to 400 parts by weight, and more preferably 100 to 300 parts by weight, based on a total of 100 parts by weight of component (c). Low shrinkage agents that can be used in the present invention include homogeneous polymers such as polystyrene, poly(meth)acrylate, polyvinyl acetate, polyvinyl chloride, polyethylene, polypropylene, polyamide, polycarbonate, and cellulose polymers. selected from polymers or copolymers. Main copolymers include homopolymers of methyl methacrylate, ethyl methacrylate, butyl methacrylate and ethyl acrylate, and copolymers of methyl methacrylate with acrylic acid and methacrylic acid and/or their lower alkyl esters. Examples include copolymers of methyl methacrylate containing a small amount of one or more of lauroyl methacrylate, isobornyl methacrylate, acrylamide, hydroxyethyl methacrylate, styrene, 2-ethylhexyl acrylate, acrylonitrile, methacrylic acid, methacrylamide, methyloylacrylamide, and cetylstearyl methacrylate. be able to. Other useful copolymers include styrene-acrylonitrile, vinyl chloride-vinyl acetate, and the like. These low-shrinkage agents may be added in an amount of 0 to 100 parts by weight of components (a), (b), and (c) in the composition of the present invention.
It is used in amounts ranging from -40 parts by weight, preferably from 2 to 20 parts by weight. In addition to the above, the composition of the present invention may also contain, for example, pigments, colorants, lubricants or mold release agents, stabilizers, silane coupling agents, flame retardants, and the like.
Specific examples of pigments include titanium oxide, carbon black, and phthalocyanine. Examples of lubricants or mold release agents include aluminum, calcium, magnesium, and zinc salts of stearic acid. Stabilizers include barium, tin octoate, tris (nonylphenyl) phosphite, alkyl phenols such as BHT, quinones,
There are amines, etc. A preferred method for producing the unsaturated polyester resin composition of the present invention is as follows. That is, the first compound containing the unsaturated polyester resin which is the component (a) of the present invention and the vinyl monomer which is the component (c) of the present invention
The mixture is mixed with a second mixture containing component (b), a low shrinkage agent made of two different types of polymers, and component (c), a vinyl monomer. This is a manufacturing method in which a curing agent and, if necessary, additives such as a filler, a fiber reinforcing agent, a thickener, a low shrinkage agent, and a mold release agent are mixed into one or both of the two mixtures. In particular, it is preferable to mix the filler into the second mixture. This method is preferred for suppressing phase separation between the modified hydrogenated block copolymer and the unsaturated polyester resin. The unsaturated polyester resin composition of the present invention described above can be molded into a cured product by a method such as compression molding or injection molding, preferably through an intermediate compound such as SMC or BMC. (Effects of the Invention) The present invention improves the initial viscosity of the compound and reduces the viscosity upon heating by using a specific blending ratio of the low shrinkage agent consisting of two different types of polymers as component (b). It is possible to provide an unsaturated polyester resin composition with low surface properties, dimensional stability, and impact resistance, and its use is particularly applicable to automobile parts, transportation equipment such as boats,
It can be useful for construction equipment such as bathtubs and septic tanks, and other industrial products such as chairs. (Example) Examples are shown below, but these are intended to explain the present invention more specifically, and the present invention is not limited to these examples. (1) Preparation of unsaturated polyester resin as component (a) A mixture consisting of 0.7 mol of maleic anhydride, 1.4 mol of phthalic anhydride, 2.0 mol of propylene glycol, and 0.2 mol of diethylene glycol was heated to about 100°C under a nitrogen stream. While stirring and removing condensed water from the system, the temperature is gradually raised to approximately 210°C. At this temperature, esterification reaction occurs and oxidation occurs.
Forty unsaturated polyester resins were synthesized. This unsaturated polyester resin was dissolved in styrene, and a solution having a solid content concentration of 65% by weight was used as component (a-1). Further, a mixture of 0.6 mol of isophthalic acid, 0.6 mol of phthalic anhydride, 1.4 mol of maleic anhydride, and 2.6 mol of propylene glycol was subjected to an esterification reaction in the same manner as above to synthesize an unsaturated polyester resin with an oxidation level of 30. This unsaturated polyester resin was dissolved in styrene, and a solution having a solid content concentration of 65% by weight was used as component (a-2). (2) Synthesis of component (b) (i) hydrogenated block copolymer and its modified polymer It has a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene, and the amount of bound styrene is 30% by weight. ,
A hydrogenated block copolymer with a 1,2-vinyl bond content of 44% in the polybutadiene moiety before hydrogenation, a number average molecular weight of 79000, a molecular weight distribution of 1.05, and a hydrogenation rate of 99% is disclosed in JP-A-59-133203. It was synthesized using the Ti-based hydrogenation catalyst described above, and this product was used as the component (b--1). Next, it has a polystyrene-hydrogenated polybutadiene-polystyrene structure, with a bound styrene content of 43% by weight, a 1,2-vinyl bond content of the polybutadiene portion before hydrogenation of 52%, a number average molecular weight of 91000, and a molecular weight distribution. 1.04 and a hydrogenation rate of 96% was synthesized using a Ti-based hydrogenation catalyst described in JP-A-59-133203, and this was also used as component (b--2). Furthermore, it has a structure of polystyrene - hydrogenated polybutadiene) - ₄ Si, the amount of bound styrene is 18 parts by weight, the amount of 1,2-vinyl bonds in the polybutadiene part before hydrogenation is 29%, and the number average molecular weight
42000, a molecular weight distribution of 1.41, and a hydrogenation rate of 97% was synthesized using a Ti-based hydrogenation catalyst described in JP-A-59-133203, and this was used as component (b--3). And so. The hydrogenated block copolymer (b-
-1) to (b--3) and maleic anhydride,
A modification reaction was carried out using dicumyl peroxide to produce modified hydrogenated block copolymers (b--1-M) and (b-
-2-M) and (b--3-M) were obtained. (3) Synthesis of component (b) (ii) block copolymer and its modified polymer (polystyrene-polybutadiene) - has a ₄ Si structure, 18% by weight of bound styrene, and 1,2-vinyl in the polybutadiene part. A block copolymer having a bonding amount of 33%, a number average molecular weight of 105,000, and a molecular weight distribution of 1.33 was synthesized, and this was used as component (b--1). Next, it has a polybutadiene-polystyrene-polybutadiene-polystyrene structure, with a bound styrene content of 22% by weight, a 1,2-vinyl bond content of the polybutadiene portion of 29%, and a number average molecular weight.
A block copolymer of 111,000 and a molecular weight distribution of 1.12 was synthesized and used as component (b--2). Furthermore, it has a polystyrene-polybutadiene-polystyrene structure, with a bound styrene content of 40% by weight, a 1,2-vinyl bond content in the polybutadiene portion of 51%, a number average molecular weight of 123,000, and a molecular weight distribution.
A block copolymer of 1.26 was synthesized and used as component (b--3). The above obtained block copolymer (b--
Modified block copolymers in which 1) to (b--3) and maleic anhydride were subjected to a modification reaction without using peroxide, and 0.16 parts by weight, 0.66 parts by weight, and 1.32 parts by weight of maleic anhydride were added, respectively. (b--1-M), (b--2-M), (b
--3-M) was obtained. (b--1) of the (b) component obtained here, (b-
-2), (b--3), (b--1-M), (b
--2-M), (b--3-M), (b--
1), (b--2), (b--3), (b--
1-M), (b--2-M), (b--3-
M) is dissolved in styrene, and the solid content concentration is
A 30% by weight solution was used in the following Examples and Comparative Examples. (4) Component (c) is styrene in which the above-mentioned components (a) and (b) are dissolved. (5) Tert-butyl peroxybenzoate was used as component (d). Examples 1 to 5, Comparative Examples 1 to 2 Styrene solution of unsaturated polyester resin (a), styrene solution of low shrinkage agent (b), tert-butyl peroxybenzoate (d), zinc stearate, calcium carbonate, and Magnesium oxide was blended according to the recipe shown in Table 1 to obtain a compound before curing. This compound was aged in an oven at 40°C for 48 hours, and the viscosity of the aged compound at 23°C and the viscosity of this aged compound at 70°C were measured using a Bruckfield viscometer HBT type. The results are listed in Table 1. The results revealed that the unsaturated polyester resin composition of the present invention had a higher compound viscosity at 70°C than the comparative example, and had the characteristics of less decrease in viscosity upon heating.

[Table] Examples 6 to 10, Comparative Examples 3 to 4 Glass fiber (PPG-3198; manufactured by PPG) was added to each of the basic formulations of Examples 1 to 5 and Comparative Examples 1 to 2.
SMC was prepared by blending 100 parts of SMC and aged at 40°C for 48 hours. Thereafter, it was pressure molded at 140° C. and 85 kg/cm ² to obtain a cured unsaturated polyester resin composition. Table 2 shows the results of measuring the physical properties of each molded product. From this result, the unsaturated polyester resin composition of the present invention shows no "large undulations" or "small undulations" which are surface smoothness,
In addition, the surface gloss was 60% or more, indicating excellent surface properties. It was also found that the shrinkage rate during molding was negative (expansion), and that it had excellent effects as a low shrinkage rate. On the other hand, it has become clear that the unsaturated polyester resin composition of the present invention has a poor balance of surface smoothness, surface gloss, and low shrinkage.

【table】

Claims (1)

[Scope of Claims] 1 (a) Unsaturated polyester resin (b) A molecular unit consisting of the following components (i) and (ii), one of which contains a carboxylic acid group or a derivative group thereof. A low shrinkage agent characterized in that it is a modified polymer combined with (i) a polymer block A based on at least one vinyl aromatic compound;
A block copolymer consisting of a polymer block B mainly composed of a conjugated diene compound is hydrogenated to hydrogenate at least 80% of the aliphatic double bonds based on the conjugated diene compound in the copolymer. Hydrogenated block copolymer (ii) A polymer block A mainly composed of at least one vinyl aromatic compound and at least one
An unsaturated polyester resin composition comprising a block copolymer (c), a vinyl monomer (d) and a curing agent.