JPS59124917A - Low-shrinking unsaturated polyester resin composition - Google Patents

Abstract

PURPOSE:The titled resin composition low in curing shrinkage and capable of providing a flexible cured product, prepared by adding a (modified) vinyl acetate resin and an ethylenically unsaturated monomer to two specified kinds of unsaturated polyesters. CONSTITUTION:A low-shrinking unsaturated polyester resin composition containing (A) an unsaturated polyester having an MW, per double bond, of below 300, (B) an unsaturated polyester having an MW, per double bond, of 800-7,000, (C) vinyl acetate resin or its modified product, and (D) an ethylenically unsaturated monomer [e.g., styrene or an alkyl (meth)acrylate] at a weight ratio of A to B of 1.0-4.0 and a weight ratio of C to A+B of 0.4-0.7. It is made possible to reduce the shrinkage to a value smaller than that of conventional one, and at the same time to obtain an unsaturated polyester resin composition capable of providing an unbrittle cured product having flexible mechanical properties.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a low-shrinkage unsaturated polyester resin composition that has a low shrinkage rate upon curing and provides a flexible cured product.

Unsaturated polyester resin compositions have a large shrinkage rate during curing, so compression molded and injection molded products of unsaturated polyester resin compositions are prone to cracking and deformation.
Further, there were problems such as sink marks occurring on the back surfaces of the bosses and ribs, resulting in poor smoothness.

Recently, styrene resin, unsaturated polyester resin composition,
By mixing and curing thermoplastic resins such as acrylic resins, it has become possible to obtain cured products with less curing shrinkage, and the above-mentioned problems have been considerably improved.

However, this low shrinkage technique, as described in Japanese Patent Publication No. 46-14541, results in an optically inhomogeneous appearance after curing, and on a microscopic scale, it actually gives an inhomogeneous structure.

This phenomenon is more severe as the shrinkage reduction effect is greater9, and therefore, when attempting to reduce the amount of curing shrinkage of an unsaturated polyester resin composition to a practically sufficient level, it has the disadvantage that the cured product becomes brittle. There is.

Generally, thermofusible resins with a large low shrinkage effect are hard at room temperature, and when these thermofusible resins are mixed, even if they are dissolved in an unsaturated polyester resin composition before curing, after curing It has a structure similar to that of an unsaturated polyester resin composition completely filled with inorganic filler and becomes brittle.To improve this brittleness, it is also possible to select a resin or rubber that is soft at room temperature as a heat-resistant resin. However, in this case, it is necessary to mix a variety of resins and rubbers in order to provide sufficient low shrinkage, which improves the brittleness of the cured product, but increases the price and reduces mechanical strength. decreases.

In addition, in the composition of unsaturated polyester, by reducing the amount of unsaturated acid component to lower the three-dimensional crosslinking density of unsaturated polyester resin, or by appropriately selecting the types of acid component and glycol component, unsaturated polyester resin itself can be improved. Although there are methods to improve the brittleness of the material, similar to the above, there are drawbacks such as a decrease in mechanical strength and a failure to fully demonstrate the low shrinkage effect.

In this way, the method of reducing the shrinkage of unsaturated polyester resin compositions by mixing thermoplastic resins reduces the shrinkage rate, but on the other hand,
This has an unfavorable relationship in that the cured product becomes brittle.

On the other hand, low shrinkage unsaturated polyester resin compositions include SMC,
F manufactured by resin compositions such as BMC, hand lay-up method, preform matched domestic tie method, etc.
It is used as a resin composition for B I), especially SMC.
Due to its low shrinkage properties, the surface smoothness of the cured product is not satisfactory, so its application to automobile exterior parts is attracting attention.

However, as mentioned above, since the low shrinkage unsaturated polyester resin composition is brittle, the actual situation is that one has to be very careful when applying it.

The present invention makes it possible to reduce the shrinkage of an unsaturated polyester resin composition by mixing such a thermofusible resin to an even lower level than before, and also to reduce the embrittlement (strength The object of the present invention is to provide a low-shrinkage unsaturated polyester resin composition that does not cause a decrease in elasticity or an increase in elastic modulus, and can yield a cured product having more aggressively flexible mechanical properties.

"Honbatsuri" is an unsaturated polyester (A) with a molecular cap of 300 or less per double bond, and a molecular cap of 1 molecule per double bond.
Contains an unsaturated polyester (B) with a 1t of 800 or more and 7,000 or less, a vinyl acetate resin or a modified resin thereof (C), and an ethylenically unsaturated monomer (D).

Unsaturated polyester (Al and unsaturated polyester (B)
The mixing mass ratio ■/(B) with 1.0 or more and 4.0 or less.

Vinyl acetate resin or its modified resin (C1 and the above-mentioned unsaturated polyester (mixing mass ratio (C) of Al and (Bl) The present invention relates to a polyester resin composition.

The above unsaturated polyester (5) and (BAH, maleic H, anhydrous maleic powder) used in the present invention.

α with fumaric acid and halogenated maleic anhydride.

β-unsaturated dibasic acids, optionally phthalic acid.

Acid components of saturated dibasic acids such as phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, succinic acid, adipic acid and ethylene glycol, diethylene glycol, norobylene glycol, cyclopylene glycol, l , 3-butylene glycol.

Neopentyl glycol, hydrogenated bisphenol A, 1.
6-hexanediol, 1,4-butylene glycol,
Obtained by reacting a glycol component such as an adduct of bisphenol A with norohylene oxide or ethylene oxide, the unsaturated polyester has a molecular weight of f per double bond.
In order to make fi (Mw/C=C) 300 or less, the molecular cap (
They are designed so that Mw/C=C) is greater than or equal to soo and less than or equal to 7,000.

Adjustment of M w/C=C can be performed by a known method. Molecule per double bond in the present invention 7
4 (Mw/C=C) is the molecular weight calculated from the synthetic charge molar composition of the acid component and glycol component used in the synthesis of unsaturated polyester, and the reaction of all dibasic acid components and all glycol components in the charge. It is obtained by dividing the model calculation value assuming that the corresponding amount of water is released by the total number of moles of double bonds. For example, maleic acid 1.0 mol, propylene glycol 1.1 mol noropylene glycol 0
．． The Mw/C=C of the unsaturated polyester with a molar composition of 1 molar excess is (98, I x 1.0 mol x 76.
I
Calculated as mol; 164.

The unsaturated polyester prisoner of the present invention has Mw/C=
C must be 300 or less.

When Mw/C=C exceeds 300, the curing linear shrinkage rate of the unsaturated polyester resin composition increases and no practical effect can be obtained. Preferably M w/C=C is 250 or less,
It becomes possible to make the curing linear shrinkage rate negative (expansion). On the other hand, Mw/C=C of unsaturated polyester (Bl) must be in the range of 800 or more and 7.000 or less, and M
When w/C=C is less than 800, the curing linear shrinkage rate of the unsaturated polyester resin composition increases, and no practical effect can be obtained.

Moreover, when Mw/C-C exceeds 7.000, the mechanical strength of the cured product of the unsaturated polyester resin composition decreases.

Further, the mixing mass ratio (A)/(B) of the unsaturated polyester (A) and the unsaturated polyester CB+ needs to be in the range of 1.0 or more and 4.0 or less, preferably 1.5.
The range is 3.0 or higher. Within this range, the shrinkage rate of the resulting unsaturated polyester resin composition can be minimized, and a cured product that is positively flexible can be obtained with almost no decrease in strength.

There are no particular restrictions on the method of synthesizing the unsaturated polyester (Al) and the unsaturated polyester (Bl) used in the present invention, and they can be produced by conventional synthesis methods.If necessary, gelation and curing properties may be adjusted during the synthesis reaction. for hydroquinone.

A polymerization inhibitor such as rosebenzoquinone, an esterification promoting catalyst, etc. may be added.

The present invention uses an unsaturated polyester (3) with a molecular weight of 300 or less per double bond and a molecular weight of 8 on the side of the double bond 9.
00 or more and 7,000 or less unsaturated polyester (B),
It contains a vinyl acetate resin or its modified resin (C), and these three components are the essential components of the present invention. It is not clear why the coexistence of these three components allows a flexible cured product to be obtained with a large shrinkage effect and no decrease in strength, but it is possible to use other thermal resins instead of acetic acid heel resin or its modified resin. Resin 1 For example, styrene resin, acrylic resin, etc. do not have a sufficient low shrinkage effect.

The mixing amount of the vinyl acetate resin or its modified resin (C) is the sum of the unsaturated polyester (5) and the unsaturated polyester (a) (5) + (Bl), and the mixing mass ratio (C)
)/ (+A) +CB questions must be between 0.4 and 0.7. If this is less than 0.4, the curing linear shrinkage rate of the unsaturated polyester resin composition will increase and no practical effect will be obtained, and if it exceeds 0.7, the mechanical strength will decrease and the The effect of firing cannot be obtained.

There are no particular restrictions on the vinyl acetate resin used in the present invention.
For example, Union Carbide's Bakelite
lite) LP-70, LP-90° NZ-5 manufactured by Nippon Gosei Kagaku Co., Ltd., etc. are used.

Acrylic acid is a modified resin for vinyl acetate.

Vinyl acetate modified with methacrylic acid or the like is used (for example, Bakelite manufactured by Union Carbide) LP-4.
OA,'! Denka ASRrM-4J manufactured by Ki Kagaku Kogyo Co., Ltd. is used.

The ethylenically unsaturated monomer used in the present invention is H,
Styrene, chlorostyrene, divinylbenzene, vinyltoluene, vinyl acetate, diallyl phthalate, alkyl esters of acrylic acid, alkyl esters of methacrylic acid, mixtures thereof, and the like are used. In the present invention, the type and amount of these ethylenically unsaturated monomers are not particularly limited, but it is preferable to use a mixture of styrene and other monomers or styrene alone, unsaturated polyester fB) and vinyl acetate resin or its modified resin (
C) (0.2 for A++ (B) + (C)
~1.0 mass times.

In the present invention, a filler (E) may be mixed if necessary, and the filler is calcium carbonate.

A variety of powdered fillers such as water-use alumina, barium sulfate, and silica-based fillers, as well as their mixed optical fillers, can be used.
The mixing amount is determined by the following four components: unsaturated polyester (A), unsaturated polyester (B), vinyl acetate resin or its modified resin (C), and ethylenically unsaturated monomer (D) in the unsaturated polyester resin composition. The mixing mass ratio (El/
((A)+(Bl+(C1+) is preferably 2.0 or more.It is already known that by including the filling Δ, a reduction in shrinkage corresponding to the volume can be achieved. However, the composition of the present invention may not only have such an effect but also have a synergistic low shrinkage effect due to the above four components.

The low shrinkage unsaturated polyester resin composition according to the present invention is a resin composition such as SMC or BMC.

It can be used as a F-P resin composition produced by a hand lay-up method, a preform mated metal die method, or the like. In this case, depending on your peace of mind, additional t
- Hardening agents such as butyl peroxybenzoate, benzoyl peroxide, methyl ethyl etone peroxide.

Hardening accelerators such as dimethylaniline, cobalt octenoate and cobalt naphthenate, mold release agents such as zinc stearate and calcium stearate, viscosity modifiers such as stearic acid and palbatic acid, magnenium hydroxide, magui oxide, /
Contains thickeners and viscosity agents such as ram, auxiliary thickeners such as polyisocyanate, fiber reinforcing agents such as glass fiber, carbon fiber, and polyamideimide fiber, and colorants whose main ingredients are titanium white, carbon black, red iron oxide, etc. You may.

The present invention will be explained with reference to Examples and Comparative Examples.

0.88 mol of maleic anhydride, 0.12 mol of isophthalic acid, 0.85 mol of propylene glycol.

Dibasic acid and glycol were weighed out so that the ratio of diethylene glycol was 0.25 mol, and charged into a 21-four-bottle flask, and then hydroquinone was added in an amount of 0.02% by mass of the total mass.

The reaction was allowed to proceed while heating and stirring from room temperature to 210°C in about 5 hours, and then further maintained at 210°C.

The reaction proceeded while maintaining the temperature and stirring. Reactant 0) 6
5 i'J J>3 When the Gardner viscosity of the steamed styrene solution reached about 8 seconds, the reaction was terminated by cooling.

Unsaturated polyester with Mw/C=C of 201 (8-1)
I got it.

0.65 mol of maleic anhydride, 0.35 mol of inphthalic acid, 0.85 mol of propylene glycol.

Dibasic acid and glycol were weighed out to a ratio of 0.25 mol of diethylene glycol and charged into a 2e fourth flask, and 0.02% of the total amount of hydroquinone was added.

The reaction proceeded while heating and stirring from room temperature to 210'C at about 5:00 + 1JI, and then the reaction proceeded while keeping the temperature at 210°C and stirring continued. 65'J[-
[When the Gardner viscosity of the styrene solution reaches about 8 seconds, the reaction is terminated by rapid cooling.

Unsaturated polyester with Mw/C=C of 290 (8-2)
I changed it.

Maleic anhydride (J, 5 mol, isophthalic! 0.5
Dibasic acid and glycol were weighed out in a ratio of 0.85 mol of propylene glycol and 0.25 mol of diethylene glycol, and charged into a 21-quart flask.
Furthermore, after charging 0.02% by mass of the total mass of hydroquinone, the reaction was proceeded by heating from room temperature to 210°C in about 5 hours with stirring, and then further heated to 210°C.
Keeps you warm.

The reaction proceeded with continued stirring. 65 substances of reactants
When the Gardner viscosity of the % styrene solution reached about 8 seconds, the reaction was terminated by rapid cooling to obtain an unsaturated polyester (A-3) with Mw/C=C of 392.

Anhydrous-q-ray/acid 01 mol, adipine mO, 9 mol,
Dibasic acid and glycol were weighed out so that the ratio of propylene glycol was 1.1 moles, and charged into a 2e four-bottle flask, and then hydroquinone was added in an amount of 0.02% by mass of the total mass. After about 5 hours, the room temperature cooled. c) 210℃
The reaction was allowed to proceed while heating and stirring until 21°C.
The reaction proceeded while keeping the temperature at 0'C and stirring continuously. When the Gardner viscosity of the 6s*xs styrene solution of the reactant reached approximately 2 seconds, the reaction was terminated by rapid cooling.

Unsaturated polyester with Mw/C-C of 1907, Le(B-
1) was obtained.

0.3 mol of maleic anhydride, 7 mol of adipic acid,
Dibasic acid and glycol were weighed out so that the ratio was 1.1 mol of propylene glycol and 0.25 mol of diethylene glycol, and charged into a 2e fourth flask, and then hydroquinone was added to make up 0.02% by mass of the total mass. The reaction proceeded while heating and stirring from room temperature to 210° C. over about 5 hours, and then the reaction proceeded while keeping the temperature at 210° C. and continuing stirring. When the Gardner viscosity of the 65-mass styrene solution of the reactant reached about 2 seconds, the reaction was terminated by rapid cooling to obtain an unsaturated polyester (B-2) having Mw/C═C of 616.

0.02 mol of maleic anhydride, mol of adipic acid O,C+S, 1.1 mol of propylene glycol; 6 Weigh the dibasic acid and glycol and charge them into the fourth flask, and then add hydroquinone to the total mass. 0.02 of
After preparing the mass percent, the temperature rises from room temperature to 21% in about 5 hours.
Warm to 0°C.

The reaction proceeded with stirring, and then was kept at 210°C and continued with stirring.

When the Gardner viscosity of a 65 mass styrene solution of the reactant reaches approximately 2 seconds, the reaction is terminated by rapid cooling, and Mw/C=
An unsaturated polyester (B-3) having C of 9,656 was obtained.

All these synthetic reactions were performed in a nitrogen stream.

The unsaturated polyester resin composition of the present invention was evaluated as a sheet molding compound as shown in Table 1. The curing shrinkage rate was measured using the JIS K 69110 disc method.9 Mechanical strength and flexibility were evaluated using bending strength and elastic modulus (both in accordance with JIS K 7023). The sheet molding compound is cured at a mold temperature of 145-150°C and a molding pressure of 8Q Kpf 7cm2. The curing time was 4 minutes.

Table 2 Sheet molding concrete land obtained by blending unsaturated polyester (A-1) or (A-2) and unsaturated polyester (B-1,) according to Example 1. As shown in Example 2, the curing shrinkage rate is extremely small and the cured product actually expands, so the surface smoothness of the cured product is excellent. In addition, the cured product had high bending strength, low bending modulus, and flexible mechanical properties. Comparative Examples 1 and 2.3 are unsaturated polyester (A-1) or unsaturated polyester (B-2)
A sheet molding compound obtained by blending or (f3-3') according to Table 1 has an increased curing shrinkage rate or a decrease in the bending strength of the cured product, making it impractical.

Comparative example 4. Comparative Example 5 is an example in which an acid-modified acrylic resin or polystyrene was used in place of the vinyl acetate resin, and the curing shrinkage rate was so large that it could not be put to practical use.

Example 3. Example 4 is an unsaturated polyester (A-i)
, unsaturated polyester (B-1) was used, and the sheet molding compounds were blended so that the mixing mass ratio diagram/(B) was 3.6 and 1.2, respectively, and both had a small curing shrinkage rate and the bending of the cured product. The strength is high and the bending modulus is also low.

On the other hand, in Comparative Example 6, the mixture 1 ratio cA)/(B) was 4.2.
Therefore, the curing shrinkage rate is large, the bending elastic modulus is large, the cured product has poor lateral smoothness, and is brittle.

Similarly, in Comparative Example 7, the mixed mass N/(B) was as small as 0.6, so the curve of the cured product was too weak to be of practical use.

Comparative Example 8 is a mixture mass ratio of vinyl acetate resin (C)/(A)
+ (Bl is small at 0.2 and curing shrinkage is surprisingly large.

Moreover, in Comparative Example 9, the mixture mass ratio (C)/(AJ + (B)
The diameter is as large as 0.95, and the strength of the cured product is so low that it cannot be put to practical use.

According to the resin composition of the present invention, the embrittlement of the cured product that occurs when reducing the shrinkage of an unsaturated polyester resin composition due to the mixing of a heat-resistant resin is eliminated, and the reduction in shrinkage is further increased. A cured product having positive 7 flexibility can be obtained.

Claims (1)

[Claims] 1. Unsaturated polyester (A) with a molecular weight per double bond of 300 or less, a molecular weight per double bond of 800
Contains an unsaturated polyester (B) with a molecular weight of 7.000 or less, a vinyl acetate resin or its modified resin (C), and an ethyl-1/one type unsaturated monomer (D), and contains an unsaturated polyester (Al
and unsaturated polyester (B) at a mixing mass ratio (3)/(
B) is i, o or more and 4.0 or less, and vinyl acetate resin or its modified resin (C1 and the above unsaturated polyester (3)
and (Bl) mixing mass ratio (C)/((A)+(B)
) is 0.4 or more and 0.7 or less.