JPH01317722A - Production of molded product - Google Patents

Abstract

PURPOSE:To obtain an excellent molded product generating no yellowing or release by applying a composition, which is prepared by mixing a specific resin being a photo-setting resin, a photopolymerization initiator and org. peroxide and contains no org. acid salt of cobalt, to a mold as gel coat and irradiating the gel coat with light to cure the same and subsequently injecting a specific monomer solution to cure the gel coat layer and the injection molded layer under heating. CONSTITUTION:One or more kind of a resin selected from a polyester resin, a vinyl ester resin and an urethane modified vinyl ester resin as a photo-setting resin is mixed with a photopolymerization initiator and org. peroxide to prepare a composition containing no org. acid salt of cobalt and this composition is applied to a mold as gel coat and irradiated with light to cure the gel coat to a desired curing degree. A monomer solution of a radical curable polymer having an MW of 5,000 or more and one or more (meth)acryloyl group in the side chain thereof is injected, and the gel coat layer and the injection molded layer are cured under heating to prepare a molded product generating no yellowing or release.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention mainly relates to the production of molded products that require aesthetic appeal, such as bathtubs, table tops, washstands, and the like.

[Conventional technology and issues]

Radical-curable resins, such as polyester resins and vinyl ester resins, can be cured by heating, but if this is attempted on an industrial scale, large heating equipment is required and costs are high, so they should be cured at the lowest possible temperature, preferably at the lowest possible temperature. There is a need for a method of curing at room temperature. However, in order to cure these curable resins at or near room temperature, an organic peroxide such as ketone peroxide is used as a curing agent, and an organic acid salt of cobalt (naphthenate, naphthenate, etc.) is used as a curing accelerator. octylate) must be used in combination.

However, when cobalt naphthenate is used, for example, it has the undesirable drawback that molded products and coatings yellow over time.

For example, when it comes to artificial marble, which is required to have an extremely light color, discoloration during use is not desirable because it greatly reduces its commercial value. Therefore, discoloration of this layer must be avoided.

However, although the use of cobalt salts is undesirable in terms of yellowing of the resin,
Until now, effective room temperature or low temperature curing of resins has not been possible without the use of this material.

Further, when an unsaturated polyester resin is used for the casting layer, the adhesion to the gel coat layer is not necessarily sufficient, and there is a risk that peeling may occur between the gel coat layer and the casting layer.

[Means and effects for solving the problem] The present inventors have made numerous attempts to avoid the use of cobalt salts, and have found that in order to prevent coloring during curing at room temperature, it is necessary to accelerate the curing of peroxide-based curing agents. We found that it is optimal to use a photocuring method without using an organic acid salt of cobalt as a cobalt agent, leading to the present invention.

Although the photocuring method was very effective in curing gel coats, other drawbacks were also discovered. When it is completely photocured to exhibit sufficient physical properties as a gel coat, it is
Peeling was likely to occur between the RP laminate or the cast layer. This drawback can be prevented by polishing the gel coat to improve its adhesion, but this significantly increases the number of man-hours and is disadvantageous in terms of productivity.

Therefore, in order to avoid this drawback, instead of completely curing with photocuring, photocuring should be used to advance the curing to an intermediate curing stage, and the final complete curing should be done using organic peroxide. Find out how you can achieve your purpose by making it work.

In addition, since a radically curable polymer having a molecular weight of 5,000 or more and having one or more (meth)acryloyl groups in the side chain is used as the resin for the casting layer, it has good adhesion to the gel coat layer and does not peel off. Not at all.

Since the curing by light in step (I) of the present invention can be easily controlled, the curing of the gel coat or the subsequent laminated portion can be adjusted to the required degree.

After the gel coat layer or, if necessary, the laminated portion is photocured, casting is performed using a radical curing resin containing a radical curing agent, and this is heated and cured together with the gel coat layer. As a result, the casting part and the gel coat part are cured and bonded together, and a strong molded product without peeling can be obtained. The heating temperature for curing is 100°C or less, preferably about 70 to 80°C.

The gel coat uses a radical curing resin that can be photocured and cured with organic peroxide. Examples include (a) polyester resin, (b) vinyl ester resin, and (c) urethane-modified vinyl ester resin.

The polyester resin (a) contains an α-β unsaturated polybasic acid or its acid anhydride as a necessary component, and the unsaturated polyester obtained by esterifying it with a polyhydric alcohol using a saturated acid in combination with a polyhydric alcohol such as styrene. It is in the form of a polymerizable hexamer.

In order to be used in the present invention, components that impart hot water resistance to the cured resin such as neopentyl glycol, hydrogenated bisphenol A, and bisphenol A propylene oxide adduct are used as polyhydric alcohol components, and isophthalic acid and terephthalic acid are used as saturated acids. desirable.

The vinyl ester resin (b) is synthesized by a reaction between an epoxy group and a carboxyl group using an epoxy resin and (meth)acrylic acid. As the epoxy resin, bisphenol-glycidyl ether type molecular weight 350~
Something in the 700th position is appropriate.

In addition to (meth)acrylic acid, it is also practical to use polybasic acids or their acid anhydrides together.

In the form utilized in the present invention, a styrene monomer, which is dissolved in a copolymerizable monomer such as styrene, is blended in an amount of 40 to 60% by weight, more generally about 50% by weight, based on the resin. use.

The urethane-modified vinyl ester resin (c) is generally made by reacting the ordinary vinyl ester resin (b) with diisocyanate and is used for prepregs, SMCs, etc., but the present invention also includes these. However, polyhydric alcohols having a bisphenol structure, such as bisphenol A, are reacted with monoepoxy compounds such as propylene oxide, ethylene oxide, and phenyl glycidyl ether to change the phenolic hydroxyl groups to alcoholic hydroxyl groups, which are then modified with urethane. .

A similar polyol component can be obtained using alkylene carbonate.

The type used in the present invention is made by reacting 2 equivalents of isocyanate groups with 1 equivalent of hydroxyl groups of these polyols having a bisphenol structure, and converting the incyanate groups into a substantially polyvalent isocyanate oligomer. It is made by reacting hydroxyl groups.

In order to make these radical curable resins photocurable as the gel coat resin of the present invention, it is necessary to use a photopolymerization initiator together. Various types of photopolymerization initiators can be used, but from the perspective of avoiding coloring of the cured gel coat layer, hydrogen abstraction types that use amines in combination are not suitable, and cleavage type radical generation sources are not suitable. (a) Acetophenone derivatives such as 2-hydroxy-2-methyl-1-phenylpropan-1-one (Merck & Co. "Darocure #11")
(b) Benzyl ketals such as hydroxy-cyclohexyl-phenyl ketone (Ciba "Irgacure #184").

The gel coat resin of the present invention uses an organic peroxide in combination for final complete curing. The type of organic peroxide used for this is not particularly specified, but in reality, the resin casting and heat curing operations to form the cast layer are performed at 100°C or below. Because there are many cases,
A type that decomposes at a relatively low temperature, for example, 80° C. or lower, is desirable.

As an example, the decomposition temperature is 1 to obtain a half-life of 10 hours.
Ketone peroxide, peroxyketal, peroxycarbonate, diacyl peroxide, below 20℃
Examples include peroxy esters. Among them, peroxycarbonate and peroxyester are advantageous,
If appropriate curing temperature and handling safety are taken into account, bis(t-butylcyclohexyl) peroxydicarbonate (Kayaku Nouri Co., Ltd. “Parkyoku Dox #1”)
6'') is suitable. Combination use with other peroxides is also possible.

The radical curable resin used for the casting layer in step (II) of the present invention has polymer side chains with a molecular weight of 5000 or more (
It is in the form of a monomer solution of a radically curable polymer having one or more meth)acryloyl groups.

This unsaturated polymer having a (meth)acryloyl group in its side chain (hereinafter simply referred to as unsaturated polymer) is synthesized by the following method.

(i) A polymer having a hydroxyl group in its side chain is reacted with an unsaturated isocyanate having a methacryloyl group.

(ii) A polymer having an epoxy group in its side chain is reacted with (meth)acrylic acid. (ii) A polymer having an acid anhydride group in its side chain is reacted with an unsaturated alcohol having a (meth)acryloyl group.

This is shown in the formula below.

(a) Urethane type unsaturated polymer ■■ Urethane type unsaturated polymer (b) Vinyl ester type lower saturated polymer Side chain epoxy group polymer Methacrylic acid CI.

Vinyl ester type unsaturated polymer (c) Ester type unsaturated polymer Ester type unsaturated polymer All polymers that are raw materials for unsaturated polymers are synthesized by polymerization of monomers, but urethane type unsaturated polymer is a side chain hydroxyl polymer. For example, cellulose derivatives can also be used, but from the viewpoint of cost and boiling resistance, vinyl monomer polymerization type is preferable.For polymerization, existing methods are adopted, but considering the handling of subsequent steps,
Direct polymerization is convenient.

These casting unsaturated polymers are used as a mixture with a monomer solution, for example styrene monomer. The mixing ratio is usually 30 to 70% in terms of polymer concentration, preferably 40 to 70%.
It is 60%.

When casting and curing the resin, a filler is usually used in combination with the casting resin to provide a suitable degree of transparency and to prevent cracks caused by heat generation during curing and molding.

Glass powder, aluminum hydroxide, etc. are commonly used as fillers. Furthermore, in the composition and method of the present invention, it is of course possible to use a coloring agent, a mold release agent, a thixotropy imparting agent, a thermoplastic polymer, etc. in combination, if necessary.

Next, in order to further explain the present invention, Examples are shown below.

Example 1 (Production of vinyl ester resin (A) for gel coat) 1 equipped with a stirrer, a reflux condenser, a gas introduction tube, and a thermometer.
1. In a separable flask, 3609.9% of bisphenol liquid resin (Epicoat 827, manufactured by Yuka Shell Epoxy Co., Ltd.) with an epoxy equivalent of 175 was added as an epoxy resin. Prepare 75y of isophthalic acid and heat at 170 to 190℃ in a nitrogen stream.
After reacting for an hour, the temperature was lowered to 135°C, and 0.3 g of hydroquinone, 86 g of methacrylic acid, 0.5 g of trimethylbenzylammonium chloride, and 1.5 g of chromium naphthenate were charged, and the reaction was carried out at 130 to 135°C in an air stream for 3 hours. After that, add 100g of styrene and add 115g of styrene.
When the reaction was continued for 1 hour at ~120°C, the acid value was 9.1. At this stage, 380 g of styrene was further added to synthesize a gel coat vinyl ester resin (A). This resin had a Hazen color number of 350 and a viscosity of 11.4 voids.

(Production of casting resin (B) (urethane type unsaturated polymer)) In a 21 separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, and a thermometer, 936 g of styrene, 2-
Hydroxylethyl methacrylate (HEMA) 130
When y was weighed out and heated at 120° C. for 6 hours in a nitrogen stream, the reaction rate reached about 42%, and as a result of gas chromatography analysis, it was determined that free HHMA was about 14% of the initially charged amount.

Add 0.2g of hydroquinone, lower the temperature to 70℃, switch to full air/flow, add isocyanate ethyl methacrylate 140#, dibutyltin dilaurate 3g, and bring the temperature to 70℃.
After reacting for 5 hours, a casting resin (B) having a Hazen color number of 30 and a viscosity of 11.4 voids was obtained. Infrared analysis confirmed that free incyanate had disappeared.

(Formation of gel coat layer) Add 5 parts of Erosil R-200 to 100 parts by weight of vinyl ester resin (A) (the same applies hereinafter), and knead with a three-roll mill.
Added thixotropic properties.

To 100 parts of this resin (A), 0.5 parts of a coupling agent (Nitto Unicar Co., Ltd. ^-174), 2 parts of "Darocure #1173" manufactured by Melta Co., Ltd. as a photoinitiator, and "Darocure #1173" manufactured by Kayaku Nouri Co., Ltd. as a photoinitiator were added. The gel coat of the present invention was prepared by adding 1 part of Parryoku Dox #16n, and this was mixed with the gel coat composition (1 part).
).

On a 30 parts m x 30 parts m x 5 gm glass plate coated with a mold release agent, apply gel coat (t) to 0.5 iz with a bar coater, wait until the coated surface is uniform, and then print. When irradiated for about 15 minutes at a distance of 30 cm under a 250 W sun lamp (manufactured by Stanley Electric Co., Ltd.), the gel coat layer was cured to the extent that it was dry to the touch.

<Casting, heating, and curing) With this as one side, another 21M thick FRP using white colored glass mat was placed, and the interval between them was 10% m. Resin (B
) 100 parts 1 200 parts of Nippon Ferro Co., Ltd. type frit B-10, 1.5 parts of Nippon Oil & Fats Co., Ltd. Perbutyl Pv,
The mixture was poured into a defoaming mold and cured at 70°C for 2 hours and at 80°C for 2 hours. After cooling and demolding, a molded product (1) was obtained.

Comparative Example 1 To 100 parts of vinyl ester resin (A), 1.5 parts of Kayaku Nouri Co., Ltd. 328E as an organic peroxide, 0.3 parts of cobalt naphthenate (6% Co), and Nippon Fine Chemical as a curing accelerator. 0.3 parts of ST Cure Co., Ltd. and 5 parts of Erosil R-Zoo were added to prepare a gel coat composition (n), and this was applied to a glass plate in the same manner as in Example 1.
After photocuring, the resin (B) was cast and cured by heating to obtain a molded article (2).

Each molded article obtained in Example 1 and Comparative Example 2 was
The sample was cut into 15 ci+ pieces, placed in a boiling test container having four circular openings with a diameter of 10 C1 on one side, with the gel coat layer facing inside, and a boiling test was conducted at a temperature of 98 to 99°C. As can be seen from Table 1, the results are shown in Table 1, the molded product produced according to the present invention was superior.

Table 1 Example 2 (Manufacture of polyester resin (C) for gel coat) 21 equipped with a stirrer, fractionation condenser, gas introduction pipe, and thermometer
In a Yotsuro flask, hydrogenated bisphenol A240y,
Neopentyl gelcol 230g, purified isophthalic acid 2
After charging 49 g of maleic anhydride and esterifying it at 190 to 210°C in a nitrogen stream to give an acid value of 21.4, maleic anhydride 1
471F was added, and esterification was continued at the same temperature until the acid value reached 37.7. Then, the temperature was lowered to 140° C., and 1.15 g of hydroquinone C and 650 g of styrene were added to produce a polyester resin (C) as a homogeneous solution.

This resin had a Hazen color number of 100 and a viscosity of 8.4 voids.

(Production of casting resin (D) (vinyl ester type unsaturated polymer) 936 g of styrene and 142 g of glycidyl methacrylate were charged into a 21 separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet tube, and a nitrogen stream was introduced. 1st year of junior high school
When heated at 20-122℃ for 6 hours, the polymerization rate was approximately 43
%, and the residual ratio of glycidyl methacrylate to the charged amount was about 16%. This includes 0.0% hydroquinone.
3g of methacrylic acid, 95y of methacrylic acid, and 5g of trimethylbenzylammonium chloride were added, the temperature was lowered to 100-105°C, and the reaction was carried out in an air stream for 12 hours. As a result of infrared analysis, it was determined that the absorption of epoxy groups had disappeared.

Add to this 130g of ethylene glycol dimethacrylate.
In addition, a casting resin (D) having a Hazen color number of 1OO1 and a viscosity of 14.1 voids was obtained.

(Formation of gel coat layer) Add Erosil R-20 to 100 parts of polyester resin (C).
0 to 2 parts, B tora 0 to a coupling agent (Shin-Etsu Chemical Co., Ltd.)
After kneading 0.5 parts of 3) to impart thixotropic properties, 100 parts of this resin was added with Ciba's "Ir" as a photoinitiator.
gaeure #181'' and 2 parts of Nippon Oil & Fats Co., Ltd. Percure 0 (1-butylperoxy 2-ethylhexanate) as a peroxide were added to prepare a photocurable gel coat composition (I[[).

In the same manner as in Example 1, on a glass plate treated with a mold release agent,
A photocurable gel coat (Iff) was applied to a thickness of 0.6 gm and irradiated for 20 minutes at a distance of 30 cm under the same sun lamp as in Example 1, and the surface of the gel coat became non-adhesive.

(Casting, heating, curing) 100 parts of casting resin (D), 200 parts of frit,
Two parts of Parryoku Dox #16 were added, and after defoaming, the mixture was cast and cured in the same manner as in Example 1 to obtain a molded article (3).

When this molded product (3) was similarly subjected to a boiling test, it was found that 5
No change in hue or appearance was observed even after 00 hours had elapsed.

Example 3 (Urethane-modified vinyl ester resin (E) for gel coat)
Synthesis) In a 21 separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet tube, 370 g of a liquid resin with an epoxy equivalent of 187 was added as an epoxy resin, and 1 g of methacrylic acid was added.
72g of chromium naphthenate, 1.5v of chromium naphthenate, 0.5g of triphenylphosphine, and 0.2g of hydroquinone were reacted for 385 hours at 130 to 135°C in an air stream.The acid value was 9.1, so 230g of styrene was added. In addition, vinyl ester resin was produced.

This is obtained by reacting 1 mole of isophorone diisocyanate with 1 equivalent of the hydroxyl group of a separately prepared bisphenol A-propylene oxide adduct (Asahi Denka Co., Ltd. BPX-111), which has isocyanate groups at both ends. 600g of a 35% styrene solution of the oligomer (the following formula),
Add 3.5 g of dibutyl pot dilaurate and place under air stream for 7 days.
The reaction was carried out at 0°C for 5 hours. As a result of infrared analysis, it was confirmed that free isocyanate groups had disappeared.

Adding 490g of styrene to this, the urethane-modified vinyl ester resin (E) has a Hazen color number of 350 and a viscosity of 9.7.
Obtained at Boyz.

(Synthesis of casting resin (F) (ester type unsaturated polymer)) 936 g of styrene was charged into a 21 separable flask equipped with a stirrer, a heating dropping funnel, a reflux condenser, and a thermometer with a gas inlet tube, and the temperature After dropping 98 g of molten maleic anhydride at 120°C over 3 hours, an additional 1.5
The temperature was maintained at the same time.

Next, 200 g of 2-hydroxyethyl methacrylate
, dibutyltin dioxide 5g, hydroquinone 0.1
g was added thereto, and the mixture was reacted at 85 to 90°C for 22 hours. As a result of infrared analysis, it was determined that about 80% of the acid anhydride groups were ring-opened.

Casting resin with Hazen color number 50 and viscosity 5.9 voids (F
)was gotten.

(Formation of gel coat 1) To 100 parts of resin (E), 3 parts of Erosil (R-200), 0.5 part of coupling agent (BN-503), 1 part of "Barkadoc X #16", Darocure#1
173'' was added to prepare a photo-curable gel coat composition, and after applying the gel coat under the same conditions as in Example 1 and photo-curing, a #360 silane-treated glass mat was placed on the gel coat composition. After being impregnated with resin and defoamed, it was photocured in the same manner.

(Casting, heating, and curing) FRP colored white was used as a back layer, and 100 parts of casting resin (F), 180 parts of frit, Percure 0 (1-butyl peroxy-2= 2 parts of ethylhexanate) was cast to a thickness of 10 iv, and 8
It was cured by heating at 0° C. for 2 hours.

This was demolded and cut, and a boiling resistance test was conducted in the same manner as in Example 1. Even after the 1000 hour boiling test, there was no yellowing or cracking of the surface gel coat layer, showing extremely excellent physical properties.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an excellent molded product without yellowing of the gel coat layer or peeling between the gel coat layer and the casting layer.

, -11 Representative Patent Attorney So Gado Sho 1,

Claims (1)

[Scope of Claims] (I) (1) As the photocurable resin, one or more types (2 or more) selected from (a) polyester resin, (b) vinyl ester resin, and (c) urethane-modified vinyl ester resin. ) A photopolymerization initiator (3) A composition prepared by mixing an organic peroxide and containing substantially no organic acid salt of cobalt is applied to a mold as a gel coat, and is irradiated with light to obtain the desired degree of curing. (II) a monomer solution of a radically curable polymer having one or more (meth)acryloyl groups in the side chain, with a molecular weight of 5,000 or more, with or without backing with glass fibers; A method for producing a molded article, which comprises casting and then heating and curing the gel coat layer and the cast layer.