JPS6327167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite foam molded product that is lightweight, flexible, and has strong physical properties.

ABS has been used for automobile interior materials, furniture surface materials, etc.
Resin is widely used in automobiles, especially in center consoles, glow box slides, etc.
An ABS resin injection molded product is used. this
ABS resin molded products have no practical problems functionally, but they lack flexibility and do not have a luxurious feel to the touch.
Due to its lack of flexibility, it was difficult to say that it was sufficient in terms of safety. Various improvement methods have been proposed to solve these problems. For example, molded products are manufactured using a method generally known as the mold coat urethane method, in which a highly durable urethane paint is applied to a mold and then reactive foaming urethane is injected into the mold to obtain a molded product. There is a way. However, this manufacturing method has disadvantages such as high raw material costs, low productivity, and insufficient balance between flexibility and strength, and has not become widely used. In addition, an injection molded product of ABS resin is used as the aggregate, and this is coated with a film produced by rotary molding or slush molding from plastisol or organosol mainly made of vinyl chloride resin, and the gap is filled with foamed polyurethane. Although the molded products obtained by this method are lightweight, flexible, and have an excellent feel, they require not only injection molding of ABS resin but also complex processes such as coating with a resin film and filling with urethane foam. It has the disadvantage of requiring a process and low productivity. Furthermore, there is a method in which a film is formed using a soft compound mainly made of vinyl chloride resin by injection molding, blow molding, etc., and the desired molded product is manufactured using the same method as described above, but this method also has the same drawbacks as described above. However, there are additional restrictions due to shape and size, and it is difficult to say that it has become widespread.

In addition, in order to simultaneously obtain the toughness of vinyl chloride resin and the flexibility of foamed urethane, there is a method of slush molding using a sol composition containing a thermally decomposable blowing agent, which has been effective to some extent.
This method has the following problems.

(1) After attaching a predetermined amount of the sol composition to the mold,
When the excess sol composition is discharged from the mold, the ungelled portion flows and sag and dents are formed, and the irregularities are enlarged during subsequent melting and foaming, making it difficult to obtain a uniform surface.

(2) When slush molding is repeatedly performed on a sol composition, the fluidity, which is an important factor in the processability of the sol composition, changes, making it difficult to obtain a uniform molded product.

The inventor of the present invention was conducting intensive studies to provide a lightweight, flexible, and strong foam molded product suitable for use in automobile interior materials such as center consoles at a low price. However, if the internal foam layer is composed of a powder molding resin composition containing a foaming agent, the above-mentioned object of the present invention can be achieved, and the above-mentioned problems caused by the foaming agent-containing sol composition can also be solved. This discovery led to the completion of the present invention.

Therefore, the gist of the present invention resides in a method for manufacturing a composite foam molded product using a slush molding die, which is characterized by passing through the following three steps.

(a) Thermoplastic resin composition filled in the mold (A)
is adhered to the mold by preheating the mold to form the first resin layer, and then the excess composition (A)
The process of ejecting from the mold.

(b) Prior to step (b), a powder molding resin composition (B) containing a pyrolyzable foaming agent is filled into a mold to which a preformed resin layer is attached, and the composition ( After forming a foamable resin layer by adhering B) to a pre-formed resin layer by its adhesiveness or residual heat, a step of discharging excess composition (B) from the mold.

(c) The mold to which the first resin layer and the foamable resin layer are attached is heated to melt the first resin layer and the foamable resin layer, and after foaming the latter, the composite foam molded product is removed from the mold. Process.

To explain the present invention in detail, the mold used in the method of the present invention can be the same mold used for conventional slush molding, and its material is not particularly limited, and is mainly made of nickel. Molds containing aluminum as the main component are often used. Those whose main component is nickel are particularly excellent in terms of electroforming workability.

The thermoplastic resin composition that becomes the first resin layer used in the method of the present invention is not particularly limited as long as it exhibits fluidity within the mold, and both sol-like compositions and powder-like compositions can be used. I can do it. Examples of sol compositions include plastisols or organosols (hereinafter simply referred to as sol compositions) made by adding a plasticizer or diluent to vinyl chloride paste resin, milk suspensions after thermoplastic resin production, and water as a dispersion medium. ,
Examples include colloidal sol (latex) containing rubber hydrocarbon as a dispersoid. Among these, the sol composition is the most preferred since it forms a uniform film. The sol composition has properties required for slush molding, such as good fluidity, sharp gelling properties,
It goes without saying that it is necessary to have rapid melting properties, good heat resistance stability, etc., but the formulation should also be prepared with consideration to the ease with which the sol composition drips when discharged from the mold. is preferable. Also,
The powder composition is not particularly limited as long as it has fluidity to the extent that it can be processed into slush. Powder molding resin compositions coated with fine-particle vinyl chloride resin produced by the company, and powder molding resin compositions made by finely pulverizing thermoplastic resins can be used.
In particular, the former powder molding composition mainly composed of vinyl chloride resin has high utility value in the present invention.

The thermoplastic resin composition (A) has physical properties during molding,
In order to improve the physical properties of molded products, auxiliary agents that are usually added to resin compositions, such as fillers, stabilizers, lubricants, flame retardants, colorants, ultraviolet absorbers, antioxidants, etc., can be used together. many.

The powder molding resin composition (B) containing a pyrolyzable blowing agent used in the method of the present invention is obtained by adding a blowing agent to the powder molding composition described in the thermoplastic resin composition (A). Any material can be used as long as it can be used and has processing characteristics similar to those of composition (A). The pyrolytic blowing agent contained in the composition (B) is not particularly limited as long as it decomposes and generates gas when heated and melted during slush molding, and general organic or inorganic chemical blowing agents may be used. used. For example, azo compounds such as azodicarbonamide, 2,2'-azobisisobutyronitrile, azohexahydrobenzonitrile, diazoaminobenzene, benzenesulfonylhydrazide, benzene-1,3-disulfonylhydrazide, diphenylsulfone- 3,
Sulfonyl hydrazide compounds such as 3'-disulfonyl hydrazide, diphenyl oxide-4,4'-disulfonyl hydrazide, N,N'-dinitrosopentamethylenetetramine, N,N'-dinitroso-N,N'-dimethyl terephthal Examples include nitroso compounds such as amides, azide compounds such as terephthal azide and P-tert-butylbenzazide, and inorganic compounds such as sodium bicarbonate, ammonium bicarbonate, and ammonium carbonate, and at least one of these is used. In the method of the present invention, it is desirable to use an auxiliary agent that promotes foaming depending on the type of foaming agent together with the pyrolytic foaming agent. Therefore, the amount of blowing agent in the powder molding resin composition (B) is 0.5 to 10% by weight, preferably 1 to 6% by weight of the resin component in the composition (B).
% by weight, and the amount of the foaming aid is preferably the same as or less than the amount of the blowing agent. The blowing agent and the blowing aid are particularly limited as long as they are present in the composition (B) so as to provide a foamed molded article with uniform foaming, a uniform surface, and no roughening of the foam cells. It's not something you can do. Specific methods of addition include, for example, dispersing the blowing agent and foaming auxiliary agent in a plasticizer and allowing the plasticizer to be absorbed into the vinyl chloride resin; Examples include a method of adhering it to a thermoplastic resin and kneading it to form the composition (B), or, most simply, a method of adding and mixing a blowing agent and a foaming aid to a powder molding composition.

To carry out the method of the present invention, first, a slush molding mold is filled with the thermoplastic resin composition (A), and the mold is preheated from the outside to a temperature of 140 to 250°C in a heating furnace, hot tube, etc. The thermoplastic resin composition (A) is applied to the inner surface of the mold, and then the mold is turned over to discharge the excess composition (A) that did not adhere to the mold.
Form a resin layer. The first resin layer may be formed by filling a preheated mold with the composition (A). The preheating temperature is appropriately selected depending on the desired wall thickness of the molded product. -(a) Step- Next, after passing through step (a), the powder molding resin composition (B) containing a pyrolytic foaming agent is placed in a slush molding mold to which a pre-formed resin layer is attached. Fill it with
The composition (B) is attached onto a pre-formed resin layer using its adhesiveness or residual heat from the previous step to form a foamable resin layer. If the adhesion of the composition (B) is insufficient, adhesion may be promoted by preheating the mold to a temperature at which the blowing agent does not decompose. Excess composition (B) is discharged by inverting the mold. −
(b) Step - In the method of the present invention, after forming the first resin layer and before forming the foamable resin layer, the second resin layer and the third resin layer are formed by the same method as the foamable resin layer formation. may be provided to form a laminated resin layer, and then a foamable resin layer may be deposited and formed on the laminated resin layer. Normally, without laminating another resin layer on the first resin layer,
A method of controlling the thickness of the first resin layer and depositing the composition (B) thereon is often used.

The method of the present invention heats the mold to which the first resin layer and the foamable resin layer are attached, melting the first resin layer and the foaming resin layer, and heating the mold to a temperature higher than the decomposition temperature of the blowing agent contained in the foamable resin layer. The foamable resin layer is foamed by increasing the temperature to a temperature of 100.degree. C. to form a composite foam molded product including the first resin layer. Although the heating temperature varies depending on the first resin layer, the foamable resin layer, the decomposition temperature of the foaming agent, etc., a temperature of about 160 to 250°C is usually appropriate. For composite foam molded products, after cooling the mold and molded product,
removed from the mold. -(c) Step- According to the method of the present invention, the problems of conventional slush molding of a sol composition containing a pyrolyzable blowing agent are solved, and a lightweight and flexible molded article can be obtained at a low price. The molded product has no pinholes or scratches on the surface layer, is strong, has an extremely beautiful appearance, and has a sufficiently foamed interior. The molded product obtained by injecting hard urethane as an aggregate into the molded product has extremely good adhesion to the urethane. In addition, excellent products can be obtained by coating molded products over aggregates such as metal or ABS resin injection molded products.

Therefore, the molded products produced by the method of the present invention have great utility as automobile center consoles, glove box slids, and the like.

Next, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example 1 65 parts by weight of diundecyl phthalate (DUP), 15 parts by weight of calcium carbonate, 100 parts by weight of vinyl chloride paste resin with a degree of polymerization () of about 1500,
A plastisol was prepared by mixing 3 parts by weight of a Ba-Zn composite liquid stabilizer, 3 parts by weight of epoxidized soybean oil, and 2.5 parts by weight of a pigment (copper-phthalocyanine blue). Next, per 100 parts by weight of vinyl chloride resin with a degree of polymerization () of about 700, 70 parts by weight of dioctyl phthalate (DOP), 10 parts by weight of butylbenzyl phthalate (BBP), 3 parts by weight of a Zn-Na liquid foaming stabilizer, 4 parts by weight of azodicarbonamide, 1 part by weight of epoxidized soybean oil, and 1 part by weight of acrylic acid-based cell conditioner were heated and stirred in a Henschel mixer to absorb and mix them, and the polymerization degree was 1 μm in average particle size. (10 parts by weight of about 850 vinyl chloride emulsion polymer resin) was added to prepare a powder molding resin composition (B) containing a chemical blowing agent.

A center console mold for forming a nickel alloy electroformed leather textured slush was filled with the sol composition. After preheating the outside of the mold in a cast oven at 250°C for 30 seconds, the excess sol composition was discharged to form a first resin layer, and then the composition (B) was filled into the mold, and the mold was heated at 250°C. After preheating the outside of the mold again for 30 seconds with a gas open at ℃, excess composition (B) was discharged from the mold to form a foamable resin layer. Next, the mold with the two types of resin layers adhered thereto was held in a gear oven at 250° C. for 4 minutes to melt and foam at the same time, yielding a foam that remained adhered to the mold. When the foam was cooled and released from the mold, a center console with an extremely beautiful surface and an excellent feel was obtained.

Example 2 Diundecyl phthalate (DUP) 80% per 100 parts by weight of vinyl chloride resin with a degree of polymerization () about 800
parts by weight, 4 parts by weight of Ba-Zn liquid composite stabilizer, 3 parts by weight of epoxidized soybean oil, 1.5 parts by weight of stearic acid,
2.5 parts by weight of the pigment (polyazoled) was heated and stirred in a Henschel mixer to absorb and mix, and then 10 parts by weight of vinyl chloride emulsion polymer resin with an average particle size of 1μ and a degree of polymerization () of about 850 was added. Thing (A)
was prepared.

Next, a composition (B) containing the chemical blowing agent described in Example 1 was prepared.

The above composition (A) was applied to a glove box slid mold for molding a nickel alloy electroformed leather textured slush.
After preheating the outside of the mold in a gas oven at 250℃ for 45 seconds, drain the excess composition (A), then fill the mold with composition (B), and heat it in a gas oven at 250℃. After preheating the mold again for 45 seconds, excess composition (B) was discharged from the mold. Next, the mold to which the resin layers (A) and (B) were attached was held in a gear oven at 250° C. for 5 minutes to melt and foam at the same time, yielding a foam that remained adhered to the mold. When the foam was cooled and released from the mold, it was a glove box slid with an extremely beautiful surface and an excellent feel.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a composite foam molded product using a slush molding die, the method comprising the following three steps: (a) Thermoplastic resin composition filled in the mold (A)
is adhered to the mold by preheating the mold to form the first resin layer, and then the excess composition (A)
The process of ejecting from the mold. (b) Prior to step (b), a powder molding resin composition (B) containing a pyrolyzable foaming agent is filled into a mold to which a preformed resin layer is attached, and the composition ( After forming a foamable resin layer by adhering B) to a pre-formed resin layer by its adhesiveness or residual heat, a step of discharging excess composition (B) from the mold. (c) After heating the mold to which the first resin layer and foamable resin layer are attached to melt the first resin layer and foamable resin layer and foaming the latter resin layer, the composite foam molded product is molded into a metal mold. The process of removing from the mold. 2 The thermoplastic resin composition (A) is plastisol or organosol. A method for producing a composite foam molded article according to claim 1. 3. The method for producing a composite foam molded article according to claim 1, wherein the thermoplastic resin composition (A) is a resin composition for powder molding. 4. The method for producing a composite foam molded article according to claim 1, wherein the first resin layer in step (a) and the preformed resin layer in step (b) are the same.