JPH02270514A - Plastic molding black lead mold - Google Patents

Abstract

PURPOSE:To perform the reinforcement of a mold structure, and prevent abrasion or failures, and thus obtaining a black lead mold having the strength for a recession and protrusion structure by constituting that a hardening substance of specific thermosetting resin (C O P N A resin) is filled into blow holes of a black lead material. CONSTITUTION:A plastic molding black lead mold comprises a black lead material, and is made such that a hardening substance of C O P N A constituted of a condensation polycyclic aromatic compound comprising a mixture selected from heavy oil of coal or petroleum, tar, pitch, or naphthalene, anthracene, coronene, and derivative having these substances as a main skeleton, a cross linking agent comprising one cyclic, or two cyclic or more aromatic cycle having at least two or more kinds of groups either hydroxymethyl group or halomethyl group, and acid catalyst is filled into blow holes of a porous black lead material. And, the black lead mold is performed the mold structural reinforcement of a porous black lead material, as a result, prevented from occurring defects due to intensively compressive injection of molten resin or abrupt compression and abrasion or failure due to hard materials mixed into the plastic material, whereby uniform products can be manufactured, which have strength for a complex recess and protrusion structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a graphite mold used in various plastic moldings such as injection molding, extrusion molding, and compression molding.

(Prior Art) Recently, there has been a demand for a high-precision plastic molding technology that is suitable for high-mix, low-volume production, and the applicant has developed a technology that can replace the conventional metal mold for plastic molding, so-called metal molds. Easy to process and has good thermal conductivity.

We have proposed a graphite mold for plastic molding made of graphite material with excellent heat resistance and self-lubricating properties (Japanese Patent Application Laid-Open No. 163-162
No. 205).

This graphite mold for plastic molding has excellent properties suitable for plastic molding as described above.

However, because the graphite material itself has a porous structure,
Concentration of molten resin, such as injection molding, in which high-temperature, high-viscosity molten resin is injected under pressure from the injection nozzle into the cavity through the mold gate, and compression molding, in which a male mold and a female mold are closed and molded while being compressed. There was a problem in that it was easy to cause defects due to pressurized injection or rapid pressurization.

In addition, in plastic molding, fillers such as calcium carbonate, wood flour, pulp, and IK base 1 quartz powder are used in plastics for various purposes such as enriching the color of the product, reinforcing it, and lowering the price. Since these hard materials are mixed into materials, there is a problem in that the gate portion and inner surface of the mold are easily worn or chipped due to these hard materials.

On the other hand, in recent years, the shapes of molds have become more complex in response to the products being molded, and many molds have a multi-shell uneven structure on the inner surface, and the strength of the mold can be improved against such an uneven structure. It has become necessary.

In this way, when molding plastics, the mold must be able to prevent chipping due to intensive pressurized injection of molten resin or sudden pressurization, prevent abrasion and chipping of hard materials mixed into plastic materials, and provide strength against uneven structures. required.

(Problem to be solved by the invention) The present invention has been made in view of the above circumstances,
By reinforcing the mold structure, plastic molding prevents chipping due to intensive pressurized injection of molten resin or sudden pressurization, wear and chipping due to hard materials mixed into the plastic material, and prevents uneven structures. The purpose is to provide a graphite mold for plastic molding that has strength.

(Means for Solving the Problems) That is, 1 the present invention is a graphite mold for plastic molding in which part or all of the r-type is made of graphite material, and the thermosetting mold is composed of the following A) B) C). 1. A graphite mold for plastic molding, characterized in that the pores of a graphite material are filled with a hardened resin (COPNA resin).

A) Coal-based or petroleum-based heavy oil, tar.

Pitch, naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, acenaphthene, acenaphthylene, berylene, coronene, and these are used as the t-skeleton. A condensed polycyclic aromatic compound consisting of a species selected from 11 species or a mixture of two or more species.

B) a III#a agent consisting of one is or two or more aromatic rings having a pair of at least one of hydroxymethyl group, heromethyl group, C) #I catalyst; This is the summary.

here,! What about orange juice? -xylylene dichlorite, p-
Xylylene glycol (1,4-benzenedimethanol), dimethyl-p-xylylene glycol, dimethyl-
m-xylylene glycol and the like.

Acid catalysts include Lewis acids such as aluminum chloride and boron fluoride, sulfuric acid, phosphoric acid, organic sulfonic acids, and carboxylic acid #1.
It is one kind or a mixture of two or more protic acids selected from protonic acids such as, and derivatives thereof.

What is the mixing ratio of the condensed polycyclic aromatic compound that constitutes the C0PNA resin, the crosslinking agent, and the acid catalyst? I! Tachibana shaved condensed polycyclic aromatic compound snow 0.5 to 4.0 (molar ratio) am, acid catalyst in the range of 0.5 to 10 wt% with respect to the mixture of the condensed polycyclic aromatic compound and the crosslinking agent It is preferable to do so.

C0PN^ resin is 1) a molten liquid obtained by heating and reacting a medium reaction product (B-stage resin) in the range of 80 to 300°C and melting it by S*, and 2) a 3-stage resin 1l11 dissolved in molten steel. These liquid C can be used as a chain
0PN^-tree can be used as an impregnating agent or coating agent in making molds.

The impregnation treatment can be carried out by immersing the graphite material in a melt or solution of C0PNA resin under reduced pressure or normal pressure, or by immersing it under reduced pressure and then applying pressure.

Further, the coating treatment is performed by applying liquid C0PNA resin to the surface of the graphite material by brush coating, roll coater spraying, dipping, or the like.

The preferred range of curing temperature is 100 to 400°C. This allows the pores of the porous graphite material to be filled with the C0PNA resin.

(Function) A graphite mold for plastic molding, which is made by filling the pores of a graphite material with a cured body of C0PNA resin, which is a thermosetting resin, has a porous structure due to the crosslinking that occurs during the curing process of C0PNA resin. The structure of the graphite material is reinforced.

Therefore, damage caused by intensive tactile pressure injection of molten resin or rapid pressurization, and wear and damage caused by hard materials mixed into the plastic material are prevented.

In addition, graphite molds for plastink molding reinforced with C0PNA resin have higher bending strength, shear strength, etc. than those made only of graphite material, and have sufficient strength for molds with complex uneven structures. can be provided.

(Example) Next, an example will be described.

After pulverizing the mixture obtained by heating and kneading a mixture of commercially available pulverized petroleum-based coke and coal tar pitch, the mixture was molded using a rubber press, fired, and graphitized to determine the coefficient of thermal expansion. (Room temperature ~ 1000℃) 4.5X10-'℃
-1, Shore hardness 52.75λ~75000 person diameter micropore volume 0.08cc/g, bulk density 1.82
An isotropic graphite material was obtained. By processing this isotropic graphite material.

A mold for injection molding was made.

As an impregnating agent, coal-based pitch (average molecular weight: 1i400) and dimethyl-m-xylylene glycol were mixed at a cell ratio of 1=2, and 5 wt of trifluoromethanesulfonic acid was added thereto.
% mixed and reacted at 120°C for 40 minutes in a nitrogen stream.
After vacuum impregnation at 50°C and curing at 200°C for 1 hour,
Post-curing treatment was performed at 250° C. for 3 hours.

Using the obtained injection mold, a plastic material containing a quartz powder filler was continuously molded for 50 hours. the result,
yI! No defects were observed. or.

Compared to a normal graphite mold, the amount of wear of the mold of this example is approximately 1/1.
It was 3.

The same isotropic graphite material as in Example 1 was processed to produce an E-type and a lower mold for compression molding.

Petroleum pitch with a softening point of 80°C (average molecular acid 340) and p
- mixing xylene glycol in a molar ratio of 1:2;
Add 5wtX p-toluenesulfonic acid and heat at 130°C.
Dissolve the C0PNA resin reacted for 40 minutes in a solvent,
Spray the solution onto the upper mold and lower mold, and after drying,
After curing at 80°C for 1 hour, post-curing treatment was performed at 250°C for 2 hours.

Using the obtained compression molding mold, 1000 molded products made of vinyl chloride resin were continuously molded. As a result, no problems such as cracking or chipping of the mold occurred.

In addition, graphite molds for plastic molding are made by impregnating or coating liquid C0PNA resin on the graphite material molded into the mold and curing it, then heating it to a temperature of 700 to 2600 in a non-oxidizing atmosphere.
It can also be produced by carbonizing C0PNA resin by heat-treating it at .degree.

In this case, a glassy carbon film can be formed on the surface of the graphite material using carbonized C0PNA resin.
This makes it possible to provide a molding surface with excellent mold releasability, and to obtain a graphite mold for plastic molding that is highly durable against plastic molding performed at high temperatures.

In addition, in particular, C0P using heavy oil, tar, and
NA resin has a much higher carbonization rate than thermosetting resins such as phenol and furan, and for this reason, the volume shrinkage is small during the heat treatment process, and the heat treatment is performed at a fast temperature increase rate. I can do it.

(Effects of the Invention) As explained above, in the graphite mold for plastic molding according to the present invention, the mold structure of the porous graphite material is reinforced by the hardened C0PNA resin, so that the molten resin is not concentrated. It prevents damage caused by pressurized injection or sudden pressure, as well as wear and tear caused by hard materials mixed into the plastic material, and provides strength against complex uneven structures, extending the life of the mold. At the same time, molding defects due to mold defects are eliminated, and it is expected that uniform products can be produced.

Furthermore, since the mold structure is reinforced throughout the mold by resin impregnation or the like, the strength of the mold can be increased evenly, unlike the case where a separate reinforcing member is attached to the mold.

Furthermore, the mold can be manufactured very easily.

Claims (1)

[Claims] A graphite mold for plastic molding in which part or all of the mold is made of a graphite material, wherein a cured body of a thermosetting resin composed of the following A) B) C) has pores of the graphite material. A graphite mold for plastic molding characterized by being filled with a graphite mold. A) Coal-based or petroleum-based heavy oil, tar, pitch,
Or naphthalene, anthracene, phenanthrene,
A fused polycyclic aromatic compound consisting of one or a mixture of two or more selected from pyrene, chrysene, naphthacene, acenaphthene, acenaphthylene, berylene, coronene, and derivatives having these as main skeletons, B) hydroxymethyl group, halomethyl A crosslinking agent consisting of one or two or more aromatic rings having two or more of at least one of the following groups; C) Acid catalyst.