JPS5935914A - Molding method of liquid resin - Google Patents

Abstract

PURPOSE:To manufacture a molded product in a short time, in a good efficiency and in an easy control of thickness by a method wherein liquid resin that has been injeced between forces holding a cavity and a core at desired clearances is heated and cooled. CONSTITUTION:A core 2 is inserted into a cavity 1 and liquid resin is injected from an injection hole 5 to the clearances between forces at the ordinary temperature. After injection of the liquid resin, heating medium is circulated from heating medium inlet pipes 3, 4 to the pipe embedded in the forces and the liquid resin is heated up to the melting temperature or reactive temperature suitable for the liquid resin. The resin that has been melted or reacted sufficiently is cooled by cooling medium and taken out as a molded product. In this way, since the force composed on a cavity and a core and having adjusted clearances are used a molded product with a desired thickness can easily be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing and molding a molded article using a liquid resin, particularly a paste-like sol, in a short time, efficiently, and whose wall thickness can be easily controlled.

Conventionally, for the purpose of making automotive interior shade shades, a method has been adopted in which a paste-like sol such as plastisol or organosol, which is mainly made of vinyl chloride resin, is processed to form a molded product.
Rotational molding and slush molding are the main methods. However, these three methods d1 cause a large loss of base-like sol;
In addition, molded products have extremely thick walls! It was impossible to control the wall thickness within a range of several centimeters from 700 μ/θθμ. For example, when designing molds: However, in conventional molded products, in order to control the thickness of the part where the wall thickness is the thinnest, more paste l-form sol is used than necessary, which is economically disadvantageous, and furthermore, it is difficult to reduce the weight. However, in both rotary molding and slush molding, it was not yet possible to apply processing such as wrinkles to the inner and outer surfaces of the molded product at the same time.Furthermore, both molding methods required the mold itself to be moved significantly during the molding process. Contained inside
It was not possible to downsize a single installation.

The present inventor has developed a method for controlling the wall thickness of large molded products.
After intensive study on how to manufacture it efficiently in a short time, we decided to use a mold with a cavity and core as a set.
It can be easily manufactured by maintaining the gap between the cavity and the core at a desired size, heating and melting the liquid resin by passing a heating medium and a cooling medium through piping provided in the cavity and the core, and then cooling it. The manufactured molded product is placed in the cavity, and the gap between the cavity and the core is expanded by replacing the core with a smaller one or by moving the core vertically. discovered that a laminated molded product could be easily produced in the same mold by injecting liquid resin such as foaming resin or foaming resin and repeating heating and cooling as necessary, and completed the present invention. reached.

An object of the present invention is to provide a method for efficiently manufacturing molded products with controlled wall thickness, especially large molded products.

]-7 The gist of the present invention is to provide a method for molding liquid resin using a mold consisting of a cavity and a core (1).
), ) J11 The above-mentioned gold in which pipes for passing heat and cooling medium are buried! (Liquid resin, which is characterized by heating and cooling the liquid resin injected into the mold while holding the cavity 0 and core at the desired dimension distance 161 using a mold)
It consists in the molding method of l'1.1 fat.

Regarding the present invention in detail, the liquid used in the method of the present invention exhibits fluidity of 1 (resin and Ul: usually 71□11), and when it is heated, melted, and cooled, the resin that becomes the molded product is formed. Good, for example, plastisol made by adding a plasticizer to paste resin, and vinyl chloride-based sol compositions such as organosol made by adding a lubricant, trilene isocyanate polymer or diphenylmethane diisonanate σ] prepolymer and Freon//impregnation. A composition of a 1/tan resin consisting of a polyester polyol and dibutyltin laurate, a composition of a diallyl phthalate resin consisting of a peroxide catalyst 1A such as sialyl phthalate 1 and 0 dibutyl peroxide, Examples include compositions such as acrylic resins comprising methylolpropane trimethacrylate and peroxide catalytic force 1, and among these, vinyl chloride sol compositions are most preferably employed in the method of the present invention.Urethane resins The composition reacts at room temperature and becomes solid, but heating to about 6θ°C is required to complete the reaction.
It can be solidified by heating at about ℃.

The mold used in the method of the present invention consists of a cavity and at least seven cores, both of which are engraved with the desired shape of the molded product.

Seven examples of the molds will be explained with reference to the drawings. Figure 1 is a perspective view of the armrest mold, and Figures 2 (a) and (b) are cross-sectional views of the mold showing the process of manufacturing the armrest. A schematic diagram of the surface is shown. In the figure, /, // are cavities, 2. 2 and 22 are cores, 3 and 3' are heating and cooling medium inlet and outlet pipes for the core; .

j', /3 is the injection port for liquid resin, B is the insulation material,! 3. /
2g is power 11 heat/cooling piping, /2 is liquid (i 11
A molded product made by heating, melting, and cooling fat, / is laminated on molded product /2 7'1. / indicates an in-yard part, respectively.

The cavity/core Ω is made of a metal with good thermal conductivity such as aluminum, and is engraved with the inner and outer shapes of the molded product. Piping is buried to heat or cool the mold. The piping may be constructed from a pipe made of stainless steel or the like, or may be constructed by drilling holes in the mold itself. These pipes usually serve both as a heating medium and as a cooling medium, but they may be provided separately. The piping includes pipes 3 for inlet and outlet of heating and cooling medium,
3', &, and \' are connected to circulate a heated or cooled medium outside the mold.

Further, when the core λ is fitted into the cavity, the mold receiving mold forms a gap having a desired distance therebetween, and is provided with an injection port j for injecting liquid resin into the gap. Of course, the core may be fitted after the liquid resin is injected into the cavity, and in this case, the injection port 3' is not particularly required. Furthermore, in consideration of the molding process, the cavity may be covered with a heat insulating layer to slow temperature changes in the cavity.

Adjustment of the gap formed by the cavity/core flood is not particularly limited, but for example, a desired gap may be formed by preparing corers with different digit sizes for seven cavities. Methods include inserting a spacer with a desired thickness into the mating surfaces of the cavity/core 2, and connecting the cavity/core with a threaded rod and moving the core vertically by rotating the threaded rod. Can be mentioned. In the method of the present invention, it is particularly preferable to provide a plurality of cores with different shapes and sizes for seven cavities in order to produce a laminated composite molded product.

To carry out the method of the present invention, a core is fitted into the cavity 7 and a liquid resin at room temperature is injected into the gap between the molds through the injection port J. Although the injection pressure depends on the viscosity of the liquid resin, a pressure of Δ゛kg/crl or less is sufficient. Liquid 41 Fat phantom force 11 Heat medium input vibrator 3, y, hot from 1
(Circulate the body through piping embedded in the mold), heat to a melting temperature or reaction temperature suitable for the liquid resin, such as plastisol, to a temperature of 750-300°C. The resin is then cooled with a cooling medium and taken out as a molded product.

However, when manufacturing a laminate molded product by the method of the present invention,
Leave the molded product of previous; 111; in the cavity/1,
The gap is enlarged by a method such as changing the size of the core, liquid resin is further injected into the gap, and heating and cooling are performed.

According to the method of the present invention, a mold with a gap between the cavity and the core (σ) 1llAj is used, so a molded product with a desired wall thickness can be easily obtained, and by adjusting this gap /θθμ It can be varied within the range of ~Jcm, and when a self-heating foamable liquid resin is used, it is possible to mold a molded product with a thickness greater than that. Furthermore, when a plurality of cores with different dimensions are used, a laminated structure such as non-foamed surface layer-customized layer, non-foamed surface layer-foamed layer-non-foamed back layer, foamed surface layer-foamed layer, etc. Various laminates are obtained. Unlike conventional molding techniques such as rotary molding and slush molding, the resulting molded products can be embossed on both sides and have ribbed edges, making them suitable for large molded products such as automobile parts that require strength. It is extremely convenient for the production of

Furthermore, since the mold used in the method of the present invention injects the liquid resin at low pressure, it does not require a highly pressure-resistant structure compared to molds for injection molding, lance transfer molding, etc., and the mold itself is relatively inexpensive. However, because it has a small heat capacity and good heat conductivity, molded products can be manufactured efficiently in a short period of time.

The method of the present invention will be explained in detail in Examples below.
The present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example/ Vinyl chloride paste resin produced by emulsion polymerization/
A plastisol was prepared by mixing parts of QOM, 1 part of trioctyl, 1 part of limeritatene θ, 3 parts of barium-zinc stabilizer, and 1 part of pigment. The plastisol was injected into a mold for a meter hood cover for an old automobile interior.2.2
The plastisol was melted by holding at 20° C. for 5 minutes, and then cooled and the molded article was taken out. The molded product was flexible and strong with an excellent surface appearance, and no unevenness in wall thickness was observed. All 20 molded products had the same weight.

Example λ Polyvinyl chloride resin (fine prefecture 1 product) / θθN parts Trioctyl trimellitate Completion θ
IBa-zn stabilizer 3” Silicone surfactant I pigment (black)
a, s z Prepare Cyplastisol according to the above formulation, foam it properly, inject it into Gold 7111J of Softer J in a 4g automobile interior glove box, and make clove hox by mechanical foam molding. Manufactured the lid.

The molded product ((J: Sonoto) had an excellent surface appearance and was strong with no pinholes. Also, the molded product had problems with conventional machine-produced Y1ν molded products (e.g. There was no uneven meat at all.

Example 3 Base resin (used in Example/) /θθ
Parts by weight allowed 14 Agent (phthalic acid diester of high M alcohol) 9θ 1Ba-Zn based stable cutting
3″ face prick (gray) x
, s n After press-fitting the plastisol having the above composition into the gap formed by the cavity//tocoa/2 of the mold for an automobile interior armrest through the injection port/j, the plastisol is inserted into the piping/3 and/
Plastisol is melted by circulating a heating medium through pipes 73 and /g, and then cooled by passing a cooling medium through pipes 73 and /g to form a molded product.
I got it. Next, remove core 2, place insert part 9 made of polypropylene, insert core 22, which is smaller than core 7. / Press fit from go. In order to complete the reaction of I/tan resin/♂, a heating medium was passed through pipes /3 and 2 and held at θ°C for 3 minutes, and after cooling, the molded product was taken out. The armrest was 1d, and the visibility to the outside was also very good.

3 Easy 1i591! II Figure 1 & J, Perspective views of seven examples of molds used in the horn method of the present invention, Figure 1 (a) and (rl) iJ: Schematic cross-sectional view of the mold representing the steps of carrying out the method of the present invention. be.

In the figure, /, // are tolerance, λ, /Ω.

22 denotes each core.

Patent applicant Mitsubishi Monzant Chemical Co., Ltd. Representative
People Ben J! li soil for good people - others/names

Claims (3)

[Claims] (1) In a method of molding liquid resin using a mold consisting of a cavity and a core, the cavity and core are placed in a desired gap using the mold in which piping for passing a heating and cooling medium is embedded. A method for molding a liquid resin, characterized by heating and cooling the liquid resin injected into the mold while being held. (2) The method for molding a liquid resin according to claim 1, wherein the liquid resin is plastisol or organosol. (3) A liquid resin molding method according to claim 7 or 2, in which the desired dimension of the gap is intermittently enlarged, and the injection of liquid resin into the gap, heating, and cooling are repeated.