JPH0585583B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a low-shrinkage unsaturated polyester resin composition, which exhibits excellent low-shrinkage properties during curing by containing a specific block copolymer, and molded products thereof. It particularly relates to a low shrinkage unsaturated polyester resin composition exhibiting good mechanical properties. Traditionally, unsaturated polyester resins have been used as raw materials for glass fiber-reinforced plastics by sheet molding compound molding methods, bulk molding compound molding methods, hand lay-up molding methods, resin injection molding methods, etc. It has been used as a raw material for resin concrete using aggregates such as aluminum or silica sand, and also as a material for casting. However, unsaturated polyester resin shrinks in volume by 5 to 12% during curing, so no matter which molding method is used, the molded product is likely to suffer from a decrease in strength and cracks due to curing shrinkage. Furthermore, it has the disadvantage that surface stains, warping, and distortion occur frequently, and furthermore, it tends to peel off at the interface with glass fibers and aggregates that are reinforcing materials. [Prior Art] As a method for reducing curing shrinkage of the unsaturated polyester resin, a method has been used in which a thermoplastic resin such as polystyrene, polymethacrylate, polyvinyl acetate, etc. is blended with the unsaturated polyester. It is known that this method can achieve a certain degree of curing shrinkage reduction effect, but
However, the effect is insufficient, the mechanical strength of the molded product is reduced, and the thermoplastic resin bulges out on the surface of the molded product, resulting in a significantly poor appearance, which limits the field of use of the molded product. Therefore, in order to improve the dispersion stability of thermoplastic resin in unsaturated polyester and to improve the low shrinkage and mechanical strength of molded products,
Publication No. 23615 discloses the use of polyvinyl acetate with pendant peroxide groups obtained by copolymerizing t-butylperoxyallyl carbonate with vinyl acetate as a low-shrinkage agent for unsaturated polyester resins. There is. Also, JP-A-56-
Publication No. 79113 proposes adding a block copolymer of polyvinyl acetate and polystyrene to obtain a low-shrinkage unsaturated polyester resin with excellent surface smoothness and mechanical strength. [Problems to be Solved by the Invention] However, although molded products containing polyvinyl acetate with pendant peroxide groups as described above are considerably improved in mechanical strength, they are still inferior in terms of curing shrinkage. It wasn't enough. On the other hand, molded products to which a block copolymer of polyvinyl acetate and polystyrene was added were sufficient in terms of curing shrinkage, but insufficient in mechanical strength. Therefore, these additives can be added to the bath,
There have been problems with adding it as a low-shrinkage agent to materials used in plumbing areas such as toilets, kitchens, and washrooms, as well as automobile exterior panels and housings for electrical parts. [Means for Solving the Problems] As a result of intensive research to improve these conventional drawbacks, the present inventors have developed a block copolymer in which specific peroxide groups are pendant to an unsaturated polyester resin composition. By adding , a sufficient curing shrinkage reduction effect can be obtained, and the dispersion stability of the block copolymer in the unsaturated polyester resin is also good. As a result, it has excellent mechanical strength and water resistance, and also has a good surface gloss. The inventors have also discovered that an excellent unsaturated polyester resin composition can be obtained, and have completed the present invention. That is, the present invention provides an unsaturated polyester resin composition comprising an unsaturated polyester and a monomer copolymerizable with the unsaturated polyester, in which a-
It contains 2 to 20% by weight of a b-type block copolymer, and is characterized in that the monomer copolymerizable with the unsaturated polyester and the a-b type block copolymer are in a non-aqueous dispersion state. The present invention relates to a low shrinkage unsaturated polyester resin composition. This a-b type block copolymer having peroxide groups pendant has a segment: 70 to 100% by weight of a styrene monomer, 30 to 0% by weight of a monomer copolymerizable with the styrene monomer, and 5-95% by weight of a polymer portion formed by polymerizing B segment: 70-100% by weight of a vinyl acetate monomer and 30-0% by weight of a monomer copolymerizable with the vinyl acetate monomer. An a-b type block copolymer consisting of 95 to 5% by weight of a polymer portion consisting of a segment having a pendant peroxide group: A portion consisting of a polymerizable peroxide group-containing monomer is pendant to at least one of the a segment and b segment, and the blending ratio thereof is from 99.9 to 99.9 of the a-b type block copolymer.
It is made by adding 0.1 to 20% by weight to 80% by weight. The unsaturated polyester used in the present invention is a conventional unsaturated polyester, and is produced from α,β-unsaturated dibasic acids, saturated dibasic acids, and glycols. Here, the α,β-unsaturated dibasic acid is, for example,
Maleic anhydride, maleic acid, fumaric acid, mesaconic acid, tetraconic acid, itaconic acid, etc., or alkyl esters thereof. In addition, saturated dibasic acids include, for example, phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, halogenated phthalic anhydride,
These include adipic acid, succinic acid, sebacic acid, etc., or their alkyl esters. Further, glycols include, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, hexylene glycol, hydrogenated bisphenol A,2,2'-
These include di(4-hydroxypropoxyphenyl)propane, 2,2'-di(4-hydroxyethoxyphenyl)propane, ethylene oxide or propylene oxide. Monomers that can be copolymerized with the unsaturated polyester mentioned above are those used in ordinary unsaturated polyester resins, such as alkenyl aromatic monomers such as styrene, α-methylstyrene, and t-butylstyrene. Further, acrylic acid, methacrylic acid, alkyl esters of methacrylic acid, and the like are used, but styrene is particularly preferred. The blending ratio of these unsaturated polyesters and monomers copolymerizable with the unsaturated polyesters is usually 20 to 70% by weight of the unsaturated polyester and 80 to 30% by weight of the monomers copolymerizable with the unsaturated polyester. %. a with pendant peroxide groups in the present invention
-B type block copolymer is made by adding the following peroxide group pendant segment to the a-b type block copolymer consisting of the following a segment and b segment, and the a segment is a styrene monomer. It is composed of a polymer portion formed by polymerizing a styrene monomer alone or a styrene monomer and a monomer copolymerizable with the styrene monomer. Examples of monomers copolymerizable with styrene monomers include acrylic acid,
Acrylic esters, methacrylic acid, methacrylic esters, styrene derivatives, acrylonitrile, methacrylonitrile, fumaric or maleic acid derivatives, vinyl ketones, vinylpyridine,
Examples include butadiene, and the amount used is limited to 30% by weight or less in the polymer portion with styrene monomer. If it exceeds 30% by weight, a-
The performance of the b-type block copolymer is poor, and the dimensional stability, colorability, surface smoothness, and mechanical strength of the obtained molded product are adversely affected. Moreover, the b segment is composed of a polymer portion formed by polymerizing a vinyl acetate monomer alone or a vinyl acetate monomer and a monomer copolymerizable therewith. Examples of monomers that can be copolymerized with vinyl acetate monomer include vinyl valerate, vinyl caproate, vinyl succinate, and vinyl ethyl tail. 30% by weight or less in the polymer portion. 30
If the amount exceeds % by weight, sufficient low shrinkage cannot be imparted to the obtained molded product. Furthermore, in the segment having a pendant peroxide group, a portion consisting of a peroxide group-containing monomer copolymerizable with the monomer constituting the polymer portion of the a segment and the b segment is a portion of the segment having a pendant peroxide group. It is a pendant on at least one side of the b segment. The peroxide group-containing monomer is one that does not decompose under the conditions for obtaining the a-b type block copolymer, such as tertiary butyl peroxyallyl carbonate, tertiary amyl peroxyallyl carbonate, tertiary amyl peroxyallyl carbonate, hexylperoxyallyl carbonate, tertiary butylperoxyallyloxyethyl carbonate, tertiary amylperoxyallyloxyethyl carbonate, tertiary hexylperoxyallyloxyethyl carbonate, tertiary hexylperoxyallyloxyethyl carbonate
Butylperoxyethyl fumarate, tertiary aluminum peroxyethyl fumarate, tertiary hexylperoxyethyl fumarate, tertiary butylperoxyisopropyl fumarate, tertiary amylperoxyisopropyl fumarate, tertiary hexylperoxyisopropyl fumarate rate, tertiary butylperoxycyclohexyl fumarate, tertiary aluminum peroxycyclohexyl fumarate, tertiary hexylperoxycyclohexyl fumarate, tertiary butylperoxymethacryloyloxyethyl carbonate, tertiary amylperoxymethacryloyloxyethyl carbonate , tertiary hexylperoxymethacryloyloxyethyl carbonate, tertiary butylperoxycyclotonate, tertiary amylperoxycrotonate, among others, tertiary butylperoxyallyl carbonate, tertiary butylperoxyisopropyl fumarate, etc. , tertiary butylperoxymethacryloyloxyethyl carbonate is preferred. The peroxide group-pendant a-b type block copolymer of the present invention, which is composed of the above a segment, b segment, and a peroxide group pendant segment, has 5 to 95% by weight of a segment and 95% by weight. 0.1% for 99.9-80% by weight of an a-b type block copolymer consisting of ~5% by weight of b segments.
-20% by weight of peroxide group pendant segments, but in this case, if the proportion of the a segment is less than 5% by weight or the proportion of the b segment exceeds 95% by weight, the molded product Pigment dispersibility and surface smoothness deteriorate, and if the proportion of the a segment exceeds 95% by weight, that is, the proportion of the b segment is less than 5% by weight, the obtained a-b type block with pendant peroxide groups Dispersion stability when the copolymer is mixed and dispersed in an unsaturated polyester resin composition decreases. Furthermore, if the blending ratio of pendant segments with peroxide groups is less than 0.1% by weight, the effect of the pendant peroxide groups will not be exhibited, and good mechanical properties of the molded product will not be obtained;
If it exceeds, many side reactions will occur and the curing shrinkage reduction effect on the molded product will not be sufficient. a- with pendant peroxide groups of the present invention
The b-type block copolymer is usually contained in an amount of 2 to 20% by weight in the unsaturated polyester resin composition. If the content is less than 2% by weight, low shrinkage cannot be imparted to the molded product, and if it exceeds 20% by weight, the mechanical strength of the molded product will decrease and the surface smoothness will also deteriorate. This a-b type block copolymer having pendant peroxide groups consists of a monomer or a monomer mixture that becomes the a segment and b segment, and a peroxide group-containing monomer copolymerizable with them. using a polymeric peroxide (described in JP-A-53-149918) and a known manufacturing process (JP-A-56-1989).
79113) by bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, etc. The polymer peroxide in this case is, for example,

[Effect]

In the low-shrinkage unsaturated polyester resin composition of the present invention, the a-b type block copolymer containing pendant peroxide groups contained therein exhibits a curing shrinkage-reducing effect on molded products, and furthermore, The peroxide groups pendant in the block copolymer are cleaved during the curing reaction of the composition, causing crosslinking and grafting reactions with the matrix resin to increase the strength of the interface with the reinforcing material, which increases the mechanical strength of the molded product. Contributes to improvement of physical properties. [Effects of the Invention] In the present invention, by using an a-b type block copolymer with pendant peroxide groups as a low-shrinkage agent, mold contamination during molding and non-uniform curing shrinkage can be prevented. At the same time, due to the crosslinking reaction of the peroxide groups pendant in the block copolymer, there is a chemical interaction with the matrix resin and reinforcing material, resulting in a decrease in tensile strength and bending strength. It is possible to obtain molded products with excellent low shrinkage properties. [Manufacturing Examples, Comparative Manufacturing Examples, Examples, and Comparative Examples] The present invention will be described in detail below using manufacturing examples, comparative manufacturing examples, working examples, and comparative examples. Production Example 1 [a-b with pendant peroxide groups]
Production of type block copolymer] Add 1% polyvinyl alcohol aqueous solution to a glass reactor equipped with a thermometer, stirrer, and condenser.
The above ( ) Polymeric peroxide shown by the formula 0.5
After dissolving the weight part of the solution and replacing the air in the reactor with nitrogen gas, the temperature was increased to 60°C while stirring.
After polymerization for 3 hours, 250 parts by weight of a 1% aqueous polyvinyl alcohol solution and 90 parts by weight of styrene as a monomer to form the a segment were added. Next, the temperature was raised to 80°C and polymerization was continued for 7 hours to complete the polymerization.
-b type block copolymer was obtained. The amount of active oxygen in this block copolymer was measured by iodometry, and the average molecular weight was measured by gel permeation chromatography. The results are shown in Table-1. Production Examples 2 to 4 [a with pendant peroxide groups]
-Production of b-type block copolymer] In Production Example 1, vinyl acetate as a monomer to become the b segment and tertiary butyl peroxyallyl carbonate as a peroxide group-containing monomer copolymerizable with vinyl acetate. Furthermore, an a-b type block copolymer with pendant peroxide groups was prepared according to Production Example 1, except that the amount of styrene used as a monomer to form the a segment was changed as shown in Table 1. Obtained. Regarding these block copolymers, Production Example 1
The amount of active oxygen and the average molecular weight were measured in the same manner as above, and the results are shown in Table 1. Production Example 5 [a-b with pendant peroxide groups]
Production of type block copolymer] In Production Example 1, as the monomer to become the b segment, a solution of 0.5 parts by weight of polymeric peroxide represented by the above formula () dissolved in 10 parts by weight of vinyl acetate was used, Further, except for using 85 parts by weight of styrene as a monomer to become the a segment and 5 parts by weight of tertiary butylperoxymethacryloyloxyethyl carbonate as a peroxide group-containing monomer copolymerizable with it, According to Example 1, an a-b type block copolymer having pendant peroxide groups was obtained. The active oxygen content and average molecular weight of this block copolymer were measured in the same manner as in Production Example 1, and the results are shown in Table 1. Production Example 6 [a-b with pendant peroxide groups]
Production of type block copolymer] In Production Example 5, except for using 50 parts by weight of vinyl acetate as the monomer to become the b segment and 45 parts by weight of styrene as the monomer to become the a segment. According to Production Example 5, an a-b type block copolymer having pendant peroxide groups was obtained. The active oxygen content and average molecular weight of this block copolymer were measured in the same manner as in Production Example 1, and the results are shown in Table 1. Production Example 7 [a-b with pendant peroxide groups]
Production of type block copolymer] In Production Example 1, the monomer to be the b segment is a mixture of 30 parts by weight of vinyl acetate and 15 parts by weight of diisopropyl fumarate as a monomer copolymerizable with vinyl acetate, In addition, 5 parts by weight of tertiary butyl peroxyallyl carbonate as a peroxide group-containing monomer copolymerizable with them, and 50 parts by weight of styrene as a monomer to form the a segment. According to Production Example 1, an a-b type block copolymer having pendant peroxide groups was obtained. The active oxygen content and average molecular weight of this block copolymer were measured in the same manner as in Production Example 1, and the results are shown in Table 1. Production Example 8 [a-b with pendant peroxide groups]
Production of block copolymer] In Production Example 7, the monomer to become the a segment was a mixture of 30 parts by weight of styrene and 15 parts by weight of methyl methacrylate as a monomer copolymerizable with it, and A-b type with peroxide groups pendant according to Production Example 7 except that 5 parts by weight of tertiary butyl peroxymethacryloyloxyethyl carbonate was further added as a copolymerizable peroxide group-containing monomer. A block copolymer was obtained. The active oxygen content and average molecular weight of this block copolymer were measured in the same manner as in Production Example 1, and the results are shown in Table 1. Comparative Production Example 1 [a with pendant peroxide groups]
-Production of b-type block copolymer] In Production Example 1, 1.8 parts by weight of vinyl acetate as the monomer to be the b segment, and 1.8 parts by weight of vinyl acetate as the monomer to be the b segment, and Tertiary butyl peroxyallyl carbonate
An a-b type block copolymer with pendant peroxide groups was obtained in accordance with Production Example 1, except that the amount of styrene was 0.2 parts by weight and 98 parts by weight of styrene as a monomer to form the a segment. . The active oxygen content and average molecular weight of this block copolymer were measured in the same manner as in Production Example 1, and the results are shown in Table 1. Comparative Production Example 2 [Production of a-b type block copolymer] In Production Example 1, 30 parts by weight of vinyl acetate was used as the monomer to become the b segment, and 70 parts by weight of styrene was used as the monomer to become the a segment. A block copolymer was obtained in accordance with Production Example 1, except that parts by weight were used and a peroxide group-containing monomer copolymerizable with them was not used. The average molecular weight of this block copolymer was measured in the same manner as in Production Example 1, and the results are shown in Table 1. Comparative Production Example 3 [Production of peroxide group-containing polyvinyl acetate] In the same reactor as in Production Example 1, 200 parts by weight of a 1% polyvinyl alcohol aqueous solution, 94 parts by weight of vinyl acetate, and a peroxide group copolymerizable with it. After charging 6 parts by weight of tertiary butyl peroxyallyl carbonate as a monomer and replacing the air in the reactor with nitrogen gas, the temperature was maintained at 60°C with stirring for 3 hours.
After polymerization for a period of time, the polymerized product was filtered, washed with water, and dried to obtain peroxide group-containing polyvinyl acetate. Regarding this polyvinyl acetate, the amount of active oxygen and the average molecular weight were measured in the same manner as in Production Example 1, and the results are shown in Table 1. Production Example 9 [Production of unsaturated polyester solution] 812 parts by weight of fumaric acid, 498 parts by weight of isophthalic acid,
esterify 1000 parts by weight of propylene glycol in a conventional manner to obtain an unsaturated polyester, dilute the obtained unsaturated polyester with styrene to adjust the styrene concentration to 35% by weight of the total,
An unsaturated polyester solution was obtained.

[Table] Examples 1 to 8 Dispersions in which the a-b type block copolymers with pendant peroxide groups obtained in Production Examples 1 to 8 were dispersed in styrene at a concentration of 30% by weight. These were mixed with the unsaturated polyester solution obtained in Production Example 9 to produce a sheet molding compound under the blending conditions shown in Table 2.

[Table] After curing at 40℃ for 2 hours, these sheet molding compounds were molded under a molding pressure of 100Kg/
cm ² and compression molding at a press temperature of 140° C. to obtain a flat plate-shaped molded product (100 mm×150 mm, thickness 15 mm). The mechanical strength, molding shrinkage rate, and surface smoothness of each of the obtained molded products were determined by the following methods, and the results are shown in Table 3. (Mechanical strength) Based on JIS-K-6911 (general testing method for thermosetting plastics), test pieces were cut out from the above molded product, and tensile strength and Bending strength was measured. (Molding shrinkage rate) Based on JIS-K-6911 (mentioned above), diameter 90mm,
A disk with a thickness of 11 mm was separately molded by a press molding method, and the molding shrinkage rate was determined. (Surface smoothness) Surface roughness was measured using Super Test manufactured by Mitoyo Kogyo Co., Ltd. and evaluated on a three-grade scale. ◎: Surface roughness 0 to 0.5 μm ○: Surface roughness 0.5 to 1.0 μm △: Surface roughness 1.0 μm or more Example 9 In Examples 1 to 8, the peroxide group obtained in Production Example 2 was pendant. Except that the amount of the a-b type block copolymer dispersion was 50 parts by weight,
Molded products were obtained according to Examples 1 to 8, and mechanical strength, molding shrinkage rate, and surface smoothness were determined in the same manner. The results are shown in Table-3. Comparative Example 1 In Examples 1 to 8, Example 1 was used except that the a-b type block copolymer having pendant peroxide groups was the one obtained in Comparative Production Example 1.
A molded product was obtained according to 8 to 8, and tested in the same manner. The results are shown in Table-3. Comparative Example 2 In Examples 1 to 8, styrene-vinyl acetate a- containing no peroxide group obtained in Comparative Production Example 2 was used instead of the a-b type block copolymer having pendant peroxide groups. A molded article was obtained according to Examples 1 to 8 except for using the b-type block copolymer,
Tested in the same manner. The results are shown in Table-3. Comparative Example 3 In Examples 1 to 8, the peroxide group-containing polyvinyl acetate obtained in Comparative Production Example 3 was used instead of the a-b type block copolymer having pendant peroxide groups. Molded products were obtained according to Examples 1 to 8 and tested in the same manner. The results are shown in Table-3. Comparative Examples 4 and 5 In Examples 1 to 8, the blending amount of the a-b type block copolymer dispersion having pendant peroxide groups obtained in Production Example 1 was changed to 5 in Comparative Example 4.
Molded products were obtained according to Examples 1 to 8, except that the parts by weight were 100 parts by weight in Comparative Example 5, and tested in the same manner. The results are shown in Table-3.

【table】

Claims (1)

[Scope of Claims] 1. An unsaturated polyester resin composition comprising an unsaturated polyester and a monomer copolymerizable with the unsaturated polyester, in which an a-b type block having peroxide groups defined below is pendant. A low-shrinkage non-slip material containing 2 to 20% by weight of a copolymer, and characterized in that the monomer copolymerizable with the unsaturated polyester and the a-b type block copolymer are in a non-aqueous dispersion state. Saturated polyester resin composition. The a-b type block copolymer having pendant peroxide groups is obtained by adding a segment having peroxide groups pendant to the a-b type block copolymer consisting of the following a segment and b segment. The a segment, the b segment, and the pendant segment of the peroxide group are
A segment: 5 to 95% by weight of a polymer portion formed by polymerizing 70 to 100% by weight of a styrene monomer and 30 to 0% by weight of a monomer copolymerizable with the styrene monomer B segment: 95 to 5% by weight of a polymer portion obtained by polymerizing 70 to 100% by weight of vinyl acetate monomer and 30 to 0% by weight of a monomer copolymerizable with the vinyl acetate monomer Pendants of peroxide groups segment: a portion consisting of a peroxide group-containing monomer copolymerizable with the monomer constituting the polymer portion of the a segment and the b segment is pendant on at least one of the a segment and the b segment, And the blending ratio is from 99.9 to a-b type block copolymer
It is 0.1 to 20% by weight relative to 80% by weight.