JPH0739464B2 - Molding agent for molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin mold agent for molding.

More specifically, the present invention relates to a resin molding agent for molding using a main agent composed of an alicyclic epoxy resin and an inorganic powder, and a curing agent composed of an acid anhydride and an alkylamine.

Molding resin molds made with the resin mold agent of the present invention,
It is used for product models such as machine parts, jigs related to the model, molds for sheet metal molding, and molds for plastic molding.

In particular, the resin mold of the present invention can be used in fields requiring frequent model changes and when it is necessary to prepare a large amount of jigs and tools in a short period of time because it is easier to process compared to metal molds. It can greatly contribute to shortening, cost reduction and weight saving.

(Prior Art) Conventionally, a metal mold is generally used, and manufacturing is performed by machining.

Therefore, the manufacturing cost is high, the delivery time is long, and
Metal molds are heavy, have poor workability, are difficult to repair and repair, and have difficulty in maintenance during storage.

As a means for solving this, a resin mold made of a bisphenol A type epoxy resin, a novolac type epoxy resin, or the like was used, and its production was based on a "reproduction" method using a master model.

(Problems to be Solved by the Invention) However, a mold agent using these bisphenol A type epoxy resin and novolac type epoxy resin is lacking in fluidity.

In other words, when manufacturing a resin mold, it is necessary to remove bubbles in the resin during processing in order to obtain a molded product with good dimensional accuracy, that is, to obtain a resin mold with good dimensional accuracy.
Since it has no fluidity, defoaming is difficult, and productivity is poor, and at the same time, the resulting molded product lacks dimensional accuracy.

Secondly, it has poor heat resistance.

That is, among the resin molds, when used as a mold for injection molding, it is necessary to withstand a temperature of about 150 ° C, but the resin mold using the above-mentioned bisphenol A type epoxy resin is in a high temperature state of about 120 to 150 ° C. It had the drawback of becoming brittle when exposed to.

The present inventor has completed the present invention as a result of intensive research to solve these problems.

(Structure of the Invention) That is, the present invention provides (a) alicyclic epoxy resin 20 to 80% by weight (b) inorganic powder 80 to 20% by weight (c) 100 parts by weight of the total amount of (a) and (b) On the other hand, a main agent containing no lactone unit and containing 5 parts by weight or less of a polyhydric alcohol having a molecular weight of less than 1000 as a main component, and (d) an acid anhydride 95 to 99.9% by weight (e) a curing accelerator 0.05 to 5% by weight A resin mold agent for molding, which comprises a curing agent whose main component is%.

Is.

Examples of the alicyclic epoxy resin used as the resin component in the main component of the molding resin mold agent of the present invention include 3.4 epoxycyclohexenylmethyl, 3.4 epoxycyclohexanecarboxylate, dipentene diepoxide, vinylcyclohexene diepoxide, and among others, 3.4 epoxy Cyclohexenylmethyl, 3.4 epoxycyclohexanecarboxylate is preferred.

The structural formula of 3.4 epoxycyclohexanecarboxylate, which is an example of this alicyclic epoxy resin, is as follows.

The amount of these alicyclic epoxy resins used is 20-80% by weight, preferably 30-70% by weight, more preferably 40-
60% by weight.

When it is less than 20% by weight, the curing shrinkage rate and the linear expansion coefficient are small, which is preferable, but the resin amount is small, so the strength is lowered,
On the contrary, when the content is more than 80% by weight, the strength is improved, but the thermal conductivity is remarkably reduced, and the cycle is not improved as a resin mold for injection molding, and the productivity is reduced. In addition, the hardness decreases, and the shrinkage rate and linear expansion coefficient at the time of curing increase, which is not suitable.

As the inorganic powder which is another component of the main component of the molding resin mold agent of the present invention, asbestos, alumina, attabalgite, kaolin clay, volcanic ash, carbon black,
Graphite, finely divided silicic acid, calcium silicate, diatomaceous earth, magnesium oxide, titanium oxide, iron oxide, magnesium hydroxide, aluminum hydroxide, slate powder, sericite,
There are quartz powder (flint), fused silica powder, boron nitride, calcium carbonate, magnesium carbonate, talc, feldspar powder, molybdenum dioxide, barite, vermiculite, whiting, mica, wollastonite clay, gypsum (anhydrous), etc.,
These are used in an appropriate combination according to the purpose.

The purpose of mixing these inorganic powders is to improve hardness and thermal conductivity and increase specific gravity.

The roles of the various inorganic powders are as follows.

・ Talc, silica Tio ₂ : Reduces hardness shrinkage and linear expansion.

・ Glass fiber, ceramic: Increase hardness and reduce weight.

・ Carbon: Improves heat conduction and reduces weight.

Orben: Improves dispersion of metal powder and filler.

The combination differs depending on the application, and the compounding ratio also differs.

Further, when metal powder is added, olven (clay) is always added, and typical examples of the usage ratio in this case are as follows.

Metal powder 15 to 30 parts Metal powder 15 to 20 parts Orben 2 to 5 or carbon 15 to 20 Talc 30 to 10 Talc 20 to 5 Orben 2 to 3 (clay) The total amount of this inorganic powder used is 80 to 20 weight in the main agent. %, Preferably 30-70% by weight, more preferably 60-40% by weight
Is.

Orben (clay) plays a large role in uniformly dispersing these inorganic powders, but if too much orben is added, the dispersed state can be maintained, but the viscosity increases, the fluidity is lost, and defoaming is performed during resin mold production. It causes a problem in the process of and becomes unusable.

Therefore, the amount of orben (clay) and the rotation speed of the Henschel mixer at the time of mixing the inorganic powder and the epoxy resin are important points.

When the total amount of the inorganic powder used is less than 20% by weight, the amount of resin is relatively large and the strength is improved, which is preferable, but the curing shrinkage ratio and the linear expansion coefficient are large, and further,
The thermal conductivity is markedly reduced, which is not suitable.

When the proportion of this inorganic powder decreases, not only the shrinkage rate and linear expansion coefficient at the time of curing increase, but also the thermal conductivity of the resin mold decreases, and as a resin mold for injection molding, cycle-up does not occur and productivity increases. Is decreased, which is not preferable.

On the contrary, when the total amount of the inorganic powder used is more than 80% by weight, the shrinkage factor and the linear expansion coefficient at the time of curing are small, which is preferable, but the strength is decreased, which is not preferable.

The particle size of this inorganic powder is 100-500 mesh, preferably
200 to 400 mesh, more preferably around 300 mesh.

If the particle size is larger than 500 mesh, the strength and surface smoothness after molding are poor, and conversely it is not necessary to make it smaller than 100 mesh.

The polyhydric alcohol contained in the main component of the molding resin mold agent of the present invention does not contain a lactone unit that imparts flexibility or flexibility to the molded product, and it is possible to use one having a molecular weight of less than 1000. Required. More specifically, there are ethylene glycol, diethylene glycol, ethylene monoglycol, neopentyl glycol, glycerin, cyclohexanol, 1.6 hexanediol, trimethylpropane, 1.4 butanediol, pentaerythritol, etc. Among them, due to cost and harmlessness, Ethylene glycol and diethylene glycol are preferred.

The amount of these polyhydric alcohols used is 0.1-5% by weight in the main agent
However, it is preferably 0.3 to 4% by weight.

More preferably, it is 0.4 to 3.0% by weight.

If it is less than 0.1% by weight, the reaction does not proceed and it takes time to cure.

If it is more than 5.0% by weight, hardness cannot be maintained and heat resistance is poor.
It is not suitable as a mold agent.

Examples of the acid anhydride used as a component of the curing agent of the molding resin mold agent of the present invention include methyltetrahydrophthalic anhydride [trade name: HN2200, Epiclon B-570] methylendomethylenetetrahydrophthalic anhydride [trade name: Kayahard MCD , Methyl hymic acid anhydride MHAC-P,
MHAC-L] Methylbutenyl tetrahydrophthalic anhydride [Product name: YH
-360] Dodecenyl succinic anhydride, methylhexahydrophthalic anhydride [Brand name: RIKACID MH-700, Epiclon B-650,
HN5500], etc., among which methyltetrahydrophthalic anhydride,
Methylhexahydrophthalic anhydride and the like are preferable.

The amount of these acid anhydrides, which are the majority of the components of the curing agent, is calculated by the ratio of the epoxy equivalent and the acid anhydride equivalent, but the acid anhydride is 20 to 90, preferably the main agent 10 per 100 by weight.
Acid anhydride 40 to 70 to 0, more preferably, the main agent 1
The acid anhydride is 55 to 65 against 00.

If the amount of the acid anhydride is less than 20 with respect to the main agent 100 in the weight ratio, not only does it take a long time to cure, but also it does not cure sufficiently, so a certain hardness cannot be maintained, and it is unsuitable as a mold agent,
On the other hand, if it is more than 90, it is not preferable because it is sufficiently hardened but becomes brittle.

Examples of the curing accelerator for promoting the effect of the curing agent for the molding resin mold agent of the present invention include tertiary amine, boric acid ester, Lewis acid, and imidazole. Among them, benzyldimethylamine, trisdimethylaminomethylphenol. Are preferred.

The amount of these curing accelerators used is 0.05 to 5.0% by weight in the curing agent.
However, it is preferably 0.1 to 2.0% by weight.

More preferably, it is 0.1 to 0.5% by weight.

If the amount is less than 0.05% by weight, the effect of improving the curing speed is small, the loss time is long, the mold production is time-consuming, and the cost is high.

On the other hand, when the amount is more than 5% by weight, heat generation is large, the properties are uneven, and the curing speed is too fast, so that the pot life becomes short, and it becomes impossible to make a mold work.

Further, when the amount of the curing accelerator used is more than 5% by weight, not only does the hardness not appear, but also the material becomes brittle and loses heat resistance, which is not suitable as a mold agent.

Next, a procedure for producing a resin mold using the molding resin mold agent of the present invention will be described.

First, prepare the product that will be the prototype of the object you want to create and the container that will be the outer shape of the mold frame.

A mold release agent is applied to the original product, and it is placed in a container for making a mold.

The main compound and the curing agent prepared in advance are mixed in a predetermined ratio.

After mixing thoroughly, degas and pour into the container to make the mold.

De-foam again when it is poured into the container.

The container filled with the molding resin mold is placed in an oven and cured at 80 to 150 ° C for several hours.

At a time when the mold has hardened, remove it from the oven and check that it has hardened.

After confirming that it has hardened, remove the prototype product, put it in the oven again, and cure at 150-160 ° C for 5-15 hours.

The effects of the present invention will be described below with reference to examples.

Example-1 A main agent was prepared so as to have the following composition.

(A) As an alicyclic epoxy resin 3.4 Epoxycyclohexanecarboxylate (Celoxide 2021 manufactured by Daicel Chemical Industries) 53.1wt% (b) As an inorganic powder Orben (clay) 3.5wt% Iron powder 21.2wt% Talc 21.2wt% (c) Many Ethylene glycol 1.1 wt% as polyhydric alcohol Next, a curing agent was prepared to have the following composition.

(D) Tetrahydrophthalic anhydride 99.9wt% (HN-2200) as an acid anhydride (e) Benzyldiamine 0.1wt% as a curing accelerator The above-mentioned main ingredient and curing agent are mixed in the above-mentioned procedure, and then put in a container. The whole container was placed in an oven maintained at 100 ° C and left for 3 hours to cure.

Next, it was taken out of the oven, the prototype product was removed, and it was put in the oven again and completely cured at 150 ° C for 10 hours.

The resin mold taken out from the oven had sufficient hardness, strength and dimensional accuracy.

Example-2 The same procedure as in Example-1 was carried out except that diethylene glycol was used in place of ethylene glycol in Example-1, and a resin mold having sufficient hardness, strength and dimensional accuracy similar to that in Example-1 was obtained. It was

Claims (1)

[Claims] (A) 20 to 80% by weight of alicyclic epoxy resin (b) 80 to 20% by weight of inorganic powder (c) A lactone unit is added to 100 parts by weight of the total amount of (a) and (b). A main agent which does not contain and whose main component is 5 parts by weight or less of a polyhydric alcohol having a molecular weight of less than 1000, and (d) an acid anhydride of 95 to 99.9% by weight (e) a curing accelerator of 0.05 to 5% by weight. A resin mold agent for molding, comprising a curing agent that