JP2000204137A - Resin molded product, resin molded article and their production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a resin molded product having a suitable storage stability, capable of being cured in a short time, capable of omitting after-cure after being released from a mold and useful for a resin molded article such as a washbasin by adopting plural kinds of hardening accelerators mutually different in their reaction temperature regions. SOLUTION: This resin molded product is obtained by compounding (A) an epoxy resin, (B) an acid anhydride curing agent, (C) an inorganic filler as basic materials and (D) at least two kinds of hardening accelerators mutually different in their reaction temperature regions. It is preferable that the ingredient D is compounded with (i) at least one kind of latent hardening accelerators having <=70 deg.C unreacting region and (ii) at least one kind of hardening accelerators not having any unreacting temperature region, that the ingredients i and ii are included in quantities of >=2.5 wt.% and 0.01-0.5 wt.% both based on the total weight of the ingredients A and B, respectively and that the ingredient C is included in a quantity of 100-500 wt.% based on the total weight of the ingredients A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded article, a resin molded article, and a method for producing the same, which are used as sanitary ware such as a washbasin, a toilet bowl, a tank, etc., a counterpart, a bathtub, etc.

[0002]

2. Description of the Related Art Sanitary ware such as washbasins and toilets includes pottery stone,
Although baked goods using feldspar and clay as main raw materials are used,
Artificial marble with excellent design is used for counters and bathtubs.

[0003] Artificial marble was previously made of unsaturated polyester or acrylic, but had problems such as cracking and gloss.
As disclosed in JP-A-2-6359, a material prepared by adding silica or the like as a filler to a base material mainly composed of an epoxy resin, an acid anhydride curing agent, a curing accelerator, etc. is used as a mold. It was obtained by performing heat polymerization (curing) in the inside. However, since this manufacturing method is a casting method, productivity is poor.

Accordingly, as disclosed in JP-A-3-247544 or JP-A-5-238799, a base material mainly composed of an epoxy resin, an acid anhydride curing agent, a curing accelerator, etc. A method has been proposed in which a material prepared by adding silica or the like is precured into a semi-cured state, and is press-formed under heating.

[0005]

However, in the above method, the productivity up to the mold release is greatly improved as compared with the casting method, but after-curing after the mold release is required.
It contains steps that are not available in conventional unsaturated polyester or acrylic artificial marble, and the benefits of changing to epoxy artificial marble are halved.

[0006] The reason is that the amount of the curing accelerator disclosed in JP-A-3-247544 or JP-A-5-238799 is small, so that the amount of the curing accelerator per 2 mm of the molded product is 2 mm.
Molded articles molded in the in-mold curing time within about a minute are not completely cured, and require after-curing after release. If the in-mold curing time is lengthened and after-curing after mold release is to be omitted, 1 / mm
It takes about 0 minutes or more, and there is a problem in productivity. Also, if the amount of the curing accelerator is increased in order to omit the after-curing, the storage stability will be significantly shortened as described in JP-A-5-238799.

Accordingly, the present invention has been made to solve the above-mentioned problems, and has an appropriate storage stability of a resin molded product, cures in a short time, and omits after-curing after mold release. It is an object of the present invention to provide a resin molded product, a resin molded product, and a method for producing the same.

[0008]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 comprises (A) an epoxy resin, (B) an acid anhydride hardener, and (C) an inorganic filler. Is characterized in that at least two or more kinds of curing accelerators having different reaction temperature ranges are blended.

Further, the epoxy resin (A) includes:
For example, hydrogenated bisphenol A glycidyl ether and the like are mentioned. In consideration of the fluidity of the material, the viscosity of bisphenol A glycidyl ether is 150 ° C. at 25 ° C.
It is preferable that the viscosity be equal to or less than the poise. For this purpose, a reactive diluent may be added.

The acid anhydride curing agent (B) includes phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, trimellitic anhydride, Pyromellitic acid, methylhymic acid anhydride,
Maleic anhydride is conceivable, but hexahydrophthalic anhydride and methylhexahydrophthalic anhydride are preferred in order to obtain long-term weather resistance comparable to pottery. Since methylhexahydrophthalic anhydride is liquid at room temperature and hexahydrophthalic anhydride is solid at room temperature, methylhexahydrophthalic anhydride is more easily dispersed in an epoxy resin. Both can be used in combination. In addition, although the weather resistance is slightly inferior, it is methyltetrahydrophthalic anhydride that has excellent strength,
It is preferable to use this in combination with methylhexahydrophthalic anhydride. Furthermore, although the combination of bisphenol A glycidyl ether and methylhexahydrophthalic anhydride has sufficient weather resistance, if it is desired to further improve the weather resistance, an ultraviolet absorber can be added.

[0011] Further, as the inorganic filler (C),
It is at least one of silica, aluminum hydroxide and glass frit, and preferably has an average particle size of 20 μm or less in order to enhance strength and thermal shock resistance.

According to the present invention, the storage temperature of the resin composition,
By blending a curing accelerator that reacts with each of the curing temperatures into the base material, the resin has a moderate storage stability, cures in a short time, and can eliminate after-curing after mold release. A molded article and a resin molded article can be provided.

According to a second aspect of the present invention, at least one of the curing accelerators contained in the resin composition according to the first aspect is (D) a latent curing accelerator having an unreacted region of 70 ° C. or less. It is characterized by being. Further, (D) the latent curing accelerator having an unreacted temperature region of 70 ° C. or lower can be stored for a long period in an unreacted temperature region of 70 ° C. or lower without changing properties such as viscosity, In the case of a curing accelerator having the function of rapidly initiating a reaction, the basic chemical structure of which is a compound having an active hydrogen site activated in molecules at 70 ° C. or higher, a tertiary amine,
Examples of the compound include salts of imidazoles and compounds obtained by inactivating hardening accelerator particles with isocyanate, phenol, organic acid, boron, or the like. According to the present invention, 70 ° C
Since the reaction does not proceed below, it can be stored for a long time,
When the temperature exceeds 70 ° C., it is activated, and the crosslinking reaction between the epoxy resin and the acid anhydride can be promoted.

According to a third aspect of the present invention, at least one of the curing accelerators contained in the resin composition according to the second aspect is (E) a curing accelerator having no unreacted temperature region. Features. There are many types of (E) curing accelerators having no unreacted temperature region, but trisdimethylaminomethylphenol, benzyldimethylamine, DBU (bicyclic amidine), which are often used for acid anhydrides, are many practical examples. Compounds), imidazole, quaternary phosphonium salts, tin octylate, aromatic phosphines and the like. In particular, in order to improve the coloring and weather resistance and strength of the resin molded product, a quaternary phosphonium salt, an organic acid salt of DBU (bicyclic amidine compound), or a mixture thereof is preferable. According to the present invention, the reaction proceeds even during storage at 70 ° C. or lower, and an appropriate hardness can be obtained.
Further, by setting the temperature to 70 ° C. or higher, it is possible to cure in a short time.

According to a fourth aspect of the present invention, there is provided the resin composition according to the third aspect, wherein (D) is at least 2.5% by weight based on the total weight of (A) and (B). E) is 0.01% by weight or more and 0.5% by weight or less based on the total weight of (A) and (B), and (C) is 100% by weight based on the total weight of (A) and (B). % To 500% by weight. According to the present invention, only (E) contributes to the reaction in the pre-curing step for obtaining a semi-cured state and the storage step for the semi-cured resin molded product, and more than 0.01% by weight. It has storage stability because it is a trace amount of less than weight%. Next, in the press molding process,
(D) contributes to the reaction. 2.5% by weight
By the above, it is possible to cure in a short time and to omit after-curing after release.

According to a fifth aspect of the present invention, a resin molded product is obtained by pre-curing the resin composition of the fourth aspect at a temperature of 40 ° C. to 70 ° C., and then allowing the resin composition to cool at a temperature of 40 ° C. or less to a semi-cured state. It is characterized by being obtained. According to the present invention, the optimal hardness of the resin molded product before press molding can be obtained in a short time by precuring. After that, 40 ° C
By allowing to cool below, the rate of the reaction contributed by (E) becomes slow and the storage stability becomes long.

According to a sixth aspect of the present invention, in the press molding, the resin molded product according to the fifth aspect is set in a mold having a mold temperature of 110 ° C. to 150 ° C. to which a mold release agent is applied, and press molding. By doing so, it can be obtained without after-curing after release. According to the present invention, a large amount is added because (D) the latent curing accelerator having an unreacted temperature range of 70 ° C. or less does not contribute to the reaction during the precuring step and the storage step in a semi-cured state. be able to. Therefore, by adjusting the compounding ratio of (D), the in-mold curing time can be reduced to, for example, 2 minutes or less per 1 mm of the thickness of the molded article, and complete curing can be performed with the in-mold curing time. As a result, after-curing after release can be omitted.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a process diagram of a resin molded product, and FIG. 2 is a process diagram of a resin molded product. In the process diagram of the resin molded product shown in FIG. 1, after a viscosity is reduced in a preheating step of 50 ° C., a predetermined amount of an epoxy resin composition that has been vacuum-stirred is put into a polyethylene bag attached to the inner surface of the container. Fold the end of the bag out at the top so that air bubbles do not enter as much as possible,
Seal the upper part of the liquid level. This container is heated at 50 ° C. for 24 hours, and then left to cool at 25 ° C. to obtain a semi-cured resin molded product. This resin molding is stored at 25 ° C. In the process diagram of the resin molded product shown in FIG. 2, the resin molded product is set in a mold at a temperature of 140 ° C. which has been subjected to mold treatment with a release agent, pressed for 5 minutes, and demolded to form a 5 mm thick mold. Goods are obtained.

The temperature and time of the resin molded product and the resin molded product are merely examples, and the method according to the present invention is not limited to the above conditions.

FIG. 3 shows experimental results of specific examples of the present invention and comparative examples. The conditions for measuring the characteristics of each example and comparative example are as follows.

Whether or not pre-curing can be performed The resin composition is pre-cured at a predetermined temperature and time, and then allowed to cool at 25 ° C. When the temperature of the resin composition reaches 25 ° C., JIS K2207 Penetration (PV150 value)
Is measured, and those whose penetration degree can be in the range of 40 to 120 are acceptable. If it is within this range, it can be said that it is in a semi-cured state, and press molding is possible. Penetration is 40
Those that are less than will cure at the time of pre-curing,
Because molding becomes impossible, the possibility of pre-curing
Not possible (cured). On the other hand, if it exceeds 120, it cannot be said to be in a semi-cured state and remains in a liquid state.

Storage stability The penetration of the resin molded article when stored at 25 ° C. is 40
Days in the range of ~ 120. Note that fractions are rounded down.

Press molding result In the press molding, a molded product having a thickness of 5 mm after compression is charged into a 200 × 200 mold heated to 140 ° C.
Demold 5 minutes after compression. The quality of the condition after press molding is defined as good (rubber-like) if both ends bend like rubber immediately after press molding, good (optimal) if it has some rigidity, and poor if it is too soft and cannot be removed. And

Possibility of after-curing Good (rubber-like) in (2) requires after-curing, and good does not require after-curing.

Hereinafter, the embodiment of FIG. 3 and a comparative example will be described. Examples 1 to 3 In the range described in claim 1, (D) the unreacted temperature range is 70.
This is an example in which the addition amounts of a latent curing accelerator having a temperature of not more than ° C and (E) a curing accelerator having no unreacted temperature region are changed. In the second embodiment, the storage stability becomes longer when the amount of (E) is reduced with respect to the first embodiment, but the precuring time becomes longer. In the third embodiment, the first embodiment
In this case, the amount of (D) was increased based on the above, but the storage stability did not change. Comparative Example 1 This is an example in which a resin molded product cannot be produced in a liquid state without a semi-cured state unless (E) is added. Comparative Example 2 A resin molded product was formed without adding (D), but was not completely cured by press molding, and required after-curing. Comparative Example 3 In Comparative Example 2, if the amount of (E) is too large, after-curing can be omitted, but the storage stability is significantly shortened.
It is not realistic for mass production. Comparative Example 4 In the same formulation as in Example 1, if the precuring temperature is set in the reaction temperature range of (D), the precuring is cured during precuring, and a resin molded product cannot be produced.

[0026]

According to the present invention, a resin molded product is characterized in that the storage stability of the resin molded product is moderate, the resin is cured in a short time, and after-curing after releasing the mold is omitted. Articles and methods for their manufacture can be provided.

[Brief description of the drawings]

FIG. 1 is a process chart of a resin molded product.

FIG. 2 is a process chart of a resin molded product.

FIGS. 3A and 3B show the ratios of (D) a latent curing accelerator having an unreacted temperature region of 70 ° C. or less and (E) a curing accelerator having no unreacted temperature region, and FIGS. Change the curing temperature, whether semi-cured state, storage stability,
The result of press molding shows whether after-curing is possible or not.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mitsuru Kikuchi 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka F-term (reference) 4T002 CD051 DE147 DJ017 DL007 EG049 EL136 EN069 EN109 EU118 EU119 EU139 EW149 FD017 FD158 FD159 GL00 4J036 AA01 AD08 DA04 DA05 DA10 DB15 DB21 DB22 DC05 DC10 DC12 DC41 DD07 FA03 FA05 GA04 GA12

Claims (6)

[Claims] 1. A composition comprising (A) an epoxy resin, (B) an acid anhydride curing agent, and (C) an inorganic filler as a base material, wherein at least two or more types of curing accelerators having different reaction temperature ranges are blended. A resin composition. 2. At least one of the curing accelerators
The resin composition according to claim 1, wherein the type is (D) a latent curing accelerator whose unreacted region is 70 ° C or lower. 3. At least one of the curing accelerators
3. The resin composition according to claim 2, wherein the type is (E) a curing accelerator having no unreacted temperature region. 4. The resin composition according to claim 3, wherein (D) is calculated based on the total weight of (A) and (B).
5% by weight or more, (E) is 0.01% by weight or more and 0.5% by weight or less based on the total weight of the above (A) and (B) and (C)
From 100% by weight based on the total weight of (A) and (B)
A resin composition characterized by being blended in a range of 500% by weight. 5. The resin composition according to claim 4, which is heated at 40 ° C.
A resin molded product which is obtained by pre-curing at ~ 70 ° C, then cooling at 40 ° C or lower to be in a semi-cured state, and a method for producing the same. 6. The press molding, wherein the temperature of the mold coated with the release agent is 110 ° C. to 150 ° C.
A resin molded product obtained by setting and press-molding the resin molded product described in 1 above, without after-curing after mold release, and a method for producing the resin molded product.