JPH0674306B2 - Low shrinkage resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition that exhibits little shrinkage during curing, and particularly to a molding material that requires surface smoothness, and to prevent cracking. Suitable for mold material.

[Conventional technology]

A thermoplastic polymer is dissolved in an unsaturated polyester resin (hereinafter, unsaturation is omitted) or dissolved separately in a monomer and added, and the polymer is separated when the resin is cured, and the thermoplastic polymer (monomer solution) expands due to heat generation. The method of preventing the curing shrinkage of is well known, and the research and practical use thereof are also active.

There are many types of thermoplastic polymers used to prevent shrinkage (hereinafter simply referred to as polymers), and it is not an exaggeration to say that all types can be used as long as they are soluble in the monomer. is there.

In recent years, molding materials with a very smooth surface known as so-called "class A", especially SMC (Sheet Molding C)
In general, two types of polymers are used together in the ompound) and the required performance is satisfied.

[Problems to be Solved by the Invention]

However, the combined use of two kinds of polymers is troublesome to handle, the polymers are easily separated with the passage of time, and the materials are easily changed with the passage of time.

As a result of studies to achieve the object with one kind of added polymer, the present inventors have selected a type in which 0.01 equivalent or more and 1 equivalent or less of a terminal hydroxyl group of a saturated polyester having a number average molecular weight of 5000 or more is converted to an unsaturated group. The present invention has been completed by discovering that the objective can be achieved by using the graft polymer as a low shrinking agent of a polyester resin after being dissolved in a required amount of a vinyl monomer to carry out radical polymerization to form a graft copolymer. I was able to do it.

That is, in the present invention, (A) (a) the terminal group is substantially a hydroxyl group,
A saturated polyester having a number average molecular weight of 5000 or more, and (b) 0.01 equivalent or more 1 relative to 1 equivalent of the hydroxyl group
An equivalent amount or less of unsaturated isocyanate is dissolved in (c) vinyl monomer, and the graft polymer of polyester and vinyl polymer is prepared by reacting (a), (b) and (c), and [B] A low shrinkage resin composition comprising a saturated polyester resin or a vinyl ester resin is provided.

The polyester having an unsaturated bond whose end group is 0.01 equivalent or more and 1 equivalent or less used in the present invention is synthesized by reacting a saturated polyester having a hydroxyl group at the terminal with an unsaturated monoisocyanate.

There is no limitation on the raw material composition as long as the produced polyester is soluble in the monomer.

There is also a method of reacting glycidyl methacrylate with a polyester having a carboxyl group at the terminal, but it is difficult to synthesize a polyester having a high molecular weight and a carboxyl group at the terminal group.

The synthesis of a high molecular weight polyester is generally carried out by a deglycolization reaction of a low molecular weight polyester whose terminal group is a hydroxyl group, so that the terminal group is usually a hydroxyl group.

As the unsaturated monoisocyanate, diisocyanates having different reactivity of the isocyanate group, for example, 2,4-tolylene diisocyanate, isophorone diisocyanate (meth) unsaturated monoalcohol having an acryloyl group or allyl alcohol , Is synthesized by reacting according to the following formula.

In addition to this, isocyanate ethyl methacrylate Alternatively, m-isopropenyl-α, α ′ dimethylbenzyl isocyanate Etc. can be used as a suitable type for the present invention.

(Vinyl Monomer) Vinyl monomers for copolymerizing with unsaturated groups of these unsaturated isocyanates to form block polymers can be used as long as they are liquid in a polymerizable state and can dissolve polyester. Is. It may also be soluble in a common solvent.

Examples thereof are styrene, vinyltoluene, metal methacrylate and methacrylic acid esters, acrylic acid esters, acrylonitrile, methacrylonitrile, vinyl acetate, and other types that do not react with isocyanate groups.

The blending ratio of the polyester having an unsaturated terminal group of 0.01 equivalent or more and 1 equivalent or less and the vinyl monomer is 10 to 90% by weight of the polyester and 90 to 10% by weight of the vinyl monomer, preferably 20 to 80% by weight of the polyester and 80 to 80% of the vinyl monomer. 20% by weight.

Depending on the concentration of unsaturated bonds, gelation tends to occur during copolymerization of vinyl monomers, and proper use of a chain transfer agent is essential.

The polymerization method may be any existing method and is not particularly limited.

(Polyester Resin) The polyester resin used in the present invention is not particularly limited in its composition, but in the case of low shrinkage due to heat curing, a highly reactive type having a heat distortion temperature of 130 ° C. or higher is desirable and cast When the resin is cured at room temperature or a condition close to it, the resin composition and the amount of monomers are dominant.

The α-β unsaturated polybasic acid or its acid anhydride is an essential component, and maleic anhydride, fumaric acid, and itaconic acid are common.

Examples of the polybasic acid component that is used in combination to diversify the physical properties of the polyester resin include the following types.

Phthalic anhydride, isophthalic acid, terephthalic acid and dimethyl ester, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, adipic acid, sebacic acid, het acid, and esterification in combination with the polybasic acid to form polyester Examples of the polyhydric alcohol component include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol,
Typical examples include neopentyl glycol, butanediol 1,3, butanediol 1,4, hexanediol 1,6, hydrogenated bisphenol A and bisphenol A propylene oxide adduct.

The monomer for dissolving the unsaturated alkyd to form the polyester resin is substantially styrene, and vinyltoluene and divinylbenzene are also used.

(Vinyl ester resin) The vinyl ester resin used in the present invention is a type obtained by reacting an epoxy resin with (meth) acrylic acid, and further, if necessary, further urethanizing a hydroxyl group with an unsaturated isocyanate.

It is desirable that the heat distortion temperature is 120 ° C. or higher, and as the epoxy resin, both novolac type and bisphenol type are used.

The proportion of the graft polymer, polyester resin and vinyl ester resin used varies depending on whether it is heated or at room temperature, but generally the graft polymer is 5 to 30% by weight.

The composition capable of low shrinkage according to the present invention can, of course, be used in combination with a filler, a reinforcing material, a coloring agent, a release agent and the like for practical use.

Next, in order to help understanding of the present invention, examples will be shown below.

Example 1 Synthesis of saturated polyester (A) Propylene glycol 182 was placed in a one-separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube.
g, adipic acid 292 g, esterified to an acid value of 9.1 in a nitrogen gas stream at 180 to 210 ° C, then added tetrapropyl titanate 1.2 g, and reduced the pressure to 210 to 220 ° C, 1 Torr to make the acid value substantially A saturated polyester (A) having a zero and number average molecular weight of 11,200 was synthesized. It was a light yellowish brown syrup.

Synthesis of graft polymer (B) Saturated polyester resin (A) obtained as described above
Then, 400 g of styrene was added and dissolved uniformly, and then 6 g of isocyanate ethyl methacrylate (excluding 0.07% of water content of styrene was added to 1 equivalent of hydroxyl group of polyester).
0.8 eq) Dibutyltin dilaurate 0.2g was added, 65-70
After reacting until the absorption of the isocyanate group disappears by infrared analysis at ℃, the temperature is raised to 120-125 ℃, heat-polymerized until the polymerization rate of styrene becomes about 50%, then 200 g of styrene.
Was added to obtain a graft polymer (B) with a slightly cloudy pale yellow color and a viscosity of about 141 poise.

The ratio of saturated polyester to polystyrene is about 67:33.

Synthesis of unsaturated polyester resin (C) Propylene glycol 16 was placed in a two-separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube.
0 g, diethylene glycol 223 g, maleic anhydride 196 g,
Charge 296 g of phthalic anhydride, and in a nitrogen gas stream, acid value 31.0
After esterification up to 660g styrene, hydroquinone 0.
3 g was added to obtain an unsaturated polyester resin (C) having a Hazen color number of 150 and a viscosity of 1.2 poise.

(Composition and curing) Graft polymer (B) 25 Unsaturated polyester resin (C) 75 Styrene 10 Methyl ethyl ketone peroxide 2 Cobalt naphthenate 0.5 A composition of 100 g was poured into a 200 cc polyethylene beaker and cured at 30 ° C.

A white cast product with a slight transparency is obtained, and the shrinkage rate is 0.
It was 39%.

When cast and cured with unsaturated polyester resin only
The shrinkage rate was 8.1%.

Example 2 Synthesis of saturated polyester (D) 82 g of ethylene glycol was placed in a two-separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube.
211 g of diethylene glycol, 58 dimethyl terephthalate
180-200 with 2g, zinc acetate 4g, antimony trioxide 1g
After distilling methanol at ℃, transesterification was carried out under reduced pressure of 250 to 260 ℃ and 1 Torr or less until the molecular weight of GPC analysis was 14600.

A pale yellow, transparent, semi-solid saturated polyester (D) was obtained.

Synthesis of graft polymer (E) Saturated polyester resin (D) obtained as described above
In addition, 720 g of vinyl acetate, 12 g of an adduct of 2,4-tolylene diisocyanate with an isocyanate group of 2-hydroxyethyl acrylate and a hydroxyl of 2 to 1 (0.6 equivalent of isocyanate group to 1 equivalent of OH of polyester, acetic acid (Corrected for water consumption in vinyl), and after infrared analysis at 65-70 ° C until the isocyanate group disappeared, 1300 g of methyl ethyl ketone, 15 g of lauryl mercaptan, and 15 g of azobisisobutyronitrile were added. Polymerization was carried out at 75-80 ° C in a nitrogen stream. On the way, 5 g of azobisisobutyronitrile is added 3 times every 4 hours. 200 g of methyl ethyl ketone was added to synthesize a graft polymer (E) having a viscosity of about 500 poise.

200 g of the above solution was put into a heating kneader capable of depressurization, and the temperature was raised under reduced pressure. Finally, volatile matter was distilled off at 180 to 185 ° C. to 3 to 4 Torr, and hydroquinone 0.1 g and styrene 1000 were added.
g, and dissolve it uniformly to obtain 50 of the graft polymer (E).
% Styrene solution.

(Curing test) SMC (Sheet Molding Compound) was manufactured with the following formulation.

Polyester resin (propylene glycol phthalate,
40% styrene solution) 75 Graft polymer (E) styrene solution 25 Calcium carbonate 200 Zinc stearate 5 t-Butyl perbenzoate 1.5 1/4 glass fiber 30 Magnesia 0.5 Magnesium hydroxide 1.0 145-147 ° C molding pressure 100 atm Below, the shrinkage rate was practically zero, and the surface was extremely smooth and glossy.

Example 3 Synthesis of Saturated Polyester (F) In a two-separable flask equipped with a stirrer, a fractionating condenser, a gas introduction tube, and a thermometer, the flaky polyethylene terephthalate recovered from the X-ray film was used.
When 6 g, 300 g of propylene glycol and 3 g of dibutyltin dilaurate were charged and heated at 180 to 190 ° C. for 8 hours, the free propylene glycol almost disappeared and a mixed oligomer was obtained.

To this, 219 g of adipic acid and 250 g of isophthalic acid were charged,
After advancing the esterification at 190-200 ℃ to acid value 5.7, add zinc acetate 5g, antimony trioxide 1.5g, 230-250 ℃,
Number average molecular weight proceeds with deglycolization at 0.8 to 1.2 Torr
15400 polyesters were synthesized.

A saturated polyester (F) was obtained as a slightly yellowish solid.

Preparation of Graft Polymer (G) 600 g of saturated polyester (F) was dissolved in 600 g of methyl methacrylate having a water content of 70 ppm by distilling out 600 g of saturated polyester (F) in a heating kneader, and then isophorone diisocyanate. Addition product of 1 equivalent of hydroxyl group to 2 equivalents of isocyanate group of nato and 2-hydroxypropyl methacrylate
Add 15 g (corresponding to 0.5 equivalent of unsaturated isocyanate to OH of polyester) and react at 70-75 ° C for 6 hours.
As a result of infrared analysis, it was confirmed that the free isocyanate group disappeared.

Lauryl mercaptan 9g was added, and the temperature was raised to proceed with polymerization under reflux of methyl methacrylate in a nitrogen stream, and the temperature was gradually raised with the increase of the polymerization rate, and finally about 180 ° C, 1-2
After removing volatiles under reduced pressure of Torr, the pressure was returned to normal pressure, 0.25 g of hydroquinone and then 1200 g of styrene were added, dissolved and cooled.

Graft polymer (G) (50% styrene solution) has a viscosity of about
It was obtained in the form of a white syrup of 300 poise.

Synthesis of urethane-modified vinyl ester resin (H) In a two-separable flask equipped with a stirrer, reflux condenser and thermometer, 540 g of solid epoxy resin with epoxy equivalent of 540, 86 g of methacrylic acid, 2 g of trimethylbenzylammonium chloride, 0.3 g of hydroquinone. Charge 13
When the reaction was carried out at 0 to 135 ° C for 3 hours, the acid value became substantially zero, so after dissolving in 500 g of styrene, 2,4-tolylene diisocyanate and 2 equivalents of the isocyanate group of 2-hydroxypropyl methacrylate were added. 320 g of an adduct with 1 equivalent of a hydroxyl group and 3 g of dibutyltin dilaurate are added,
After heating at 70 to 75 ° C. for 3 hours, it was confirmed by infrared analysis that free isocyanate groups had disappeared.

By adding 280 g of styrene, a urethane-modified vinyl ester resin (H) was obtained with a Gardner color number of 5 and a viscosity of 39 poises.

The heat distortion temperature of the cured resin was 134 ° C.

(Curing test) 100 parts by weight of urethane-modified vinyl ester resin (H) Graft polymer (G) (styrene solution) 26 parts t-butyl perbenzoate 2 parts Shrinkage ratio when cured at 120 ° C is 0.1 to 0.
At 12%, there was virtually no shrinkage.

However, when a 50% styrene solution of polymethylmethacrylate was used together with the same amount (26 parts) of the resin (H), the curing shrinkage rate was 5.4%, and the effect of preventing shrinkage was poor.

〔The invention's effect〕

Since the present invention is configured as described above, when the resin composition is cured, it is possible to obtain a molded product having an extremely small shrinkage factor upon curing, a smooth surface, and rich gloss.

Claims (2)

[Claims] 1. A saturated polyester having (A) (a) a terminal group substantially a hydroxyl group and a number average molecular weight of 5000 or more, and (b) 0.01 equivalent or more and 1 equivalent to 1 equivalent of the hydroxyl group.
A graft polymer of a polyester and a vinyl polymer, which is obtained by dissolving (c) a vinyl monomer in an equivalent amount of unsaturated isocyanate or less, and reacting the (a), (b), and (c), and [B] A low shrinkage resin composition comprising a saturated polyester resin or a vinyl ester resin. 2. [A] 10 to 90% by weight of a polyester having a number average molecular weight of 5000 or more and 0.01 to 1 equivalent of terminal groups having a radical-polymerizable or copolymerizable unsaturated bond and 90 to vinyl monomer. A low shrinkage resin composition comprising a polyester obtained by polymerizing 10% by weight, a graft copolymer with a vinyl polymer, and [B] an unsaturated polyester resin or a vinyl ester resin.