JPS60101014A - Manufacture of composite foamed and molded item - Google Patents

Abstract

PURPOSE:To obtain inexpensively a composite foamed and molded item using a slush molding mold which item is light in weight, flexible and tough, by making a skin out of a thermoplastic resin free of any foaming agent and an inner foamed layer out of a powder molding resin composition containing a foaming agent. CONSTITUTION:After a thermoplastic resin composition (A) located in a mold is allowed to adhere to the mold by preheating the mold to form a first resin layer, the excess amount of the composition (A) is discharged from the mold. Then a power molding resin composition (B) containing a thermally decomposable foaming agent is loaded into the mold, and is allowed to adhere to the previously formed resin layer by its adhesion or the thermal intertia thereby forming a foamable resin layer, and the excess of the composition (B) is discharged from the mold. Then the mold is heated to melt both the first resin layer and the foamable resin layer and the temperature is elevated until the foaming agent in the foamable resin layer is decomposed to foam the foamable resin layer. After the mold and the molded item are cooled, the composite foamed and molded item having the first resin layer is removed from the mold.

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 resin has been widely used for automobile interior materials, furniture surface materials, etc., and in particular, injection molded products of ABsll resin are used for automobile center consoles, glove box lids, etc.

This ABS resin molded product has no practical problems functionally, but it lacks flexibility, does not have a luxurious feel, and because of its lack of flexibility, it is difficult to be safe. Ta.

Various improvement methods have been proposed to solve these problems. For example, after applying a highly durable urethane paint to a mold, reactive foaming urethane is injected into the mold to obtain a molded product. There is a method of manufacturing molded products using a method generally called the mold coat urethane method. However, this production Jj method has disadvantages such as high raw material bypass, low productivity, and insufficient balance between flexibility and strength, and has not become widely used. Another method involves using an injection molded product of ABS resin as an aggregate, covering it with a film produced by rotary molding or slush molding from plastisol or organosol mainly made of vinyl chloride resin, and filling the gap with foamed polyurethane. Although the molded products obtained by this method are lightweight, flexible, and have an excellent feel, they are not only injection molded with A and BS resins, but also require coating with resin films and filling with urethane foam. It has the drawback that it requires a complicated process and has low productivity. Furthermore, there is a method of forming a film on a soft compound mainly made of vinyl chloride resin by injection molding, blow molding, etc., and manufacturing the desired molded product using the same method as above, but this method also has the same drawbacks as above. Furthermore, 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 pyrolytic foaming agent, but this method has been effective to some extent. However, this method has the following problems.

fil After a predetermined amount of the sol composition is attached to the mold, when the excess sol composition is discharged from the mold, the ungelled part flows, causing sagging and dents, and unevenness during subsequent melting and foaming. is enlarged, 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 interiors such as center consoles at a low price. However, if the inner foam layer is composed of a powder molding resin composition containing a foaming agent, the above-mentioned objects 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 (A) filled into the mold
is adhered to the mold by preheating the mold to form the first
After forming the resin layer, the excess composition is discharged from the mold.

(b) (Fill a powder molding resin composition (BL e) containing a pyrolyzable foaming agent into the mold in which the preformed resin layer has arrived prior to the BL process, and A process of discharging excess composition CB+ from the mold after forming a foamable resin layer by adhering it to a preformed resin layer by its adhesiveness or residual heat.

(C1 Heat 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 foam the latter, then remove the composite foam molded product from the mold.) The process of putting out.

To explain the present invention in detail, the mold used in the method of the present invention can be a mold used for conventional slush molding as is, and its material is not particularly limited, and is mainly made of nickel as a main component. Molds containing aluminum as the main component are often used. Those containing nickel as a main component 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) prepared by adding a yV1 agent or a diluent to vinyl chloride paste resin, milk suspensions of thermoplastic resin compositions, and water as a dispersion medium. Examples include colloidal sol (latex) that uses 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. In addition, the powder composition is not particularly limited as long as it has fluidity to the extent that it can be processed by slush, and for example, a plastic-absorbing vinyl chloride resin made of a tri-blend of a vinyl chloride resin and a plasticizer. Powder molding resin compositions containing finely divided vinyl chloride resin produced by emulsion polymerization and powder molding resin compositions containing finely pulverized thermoplastic resins can be used. In particular, the former is mainly composed of vinyl chloride resin. The powder molding composition has high utility value in the present invention.

Heat = (vy2 resin composition (Al is an auxiliary agent that is usually added to a resin composition to improve the physical properties during molding and the physical properties of a molded product, such as a filler, and is used in the method of the present invention. As the powder molding resin composition (B) containing a pyrolyzable blowing agent, a thermoplastic resin composition (a composition obtained by adding a blowing agent to the powder molding composition described in N) can be used; The composition (any material that has processing characteristics similar to that of Al) is fine. If so, there are no particular restrictions and general organic or inorganic chemical blowing agents can be used.For example, azodicarpo/amide, co-!-azobisisobutyronitrile, azohexahydrobenzonitrile, diazoaminobenze 7 azo compounds such as benzenesulfonylhydrazide, benzene-/,3-disulfonylhydrazide, diphenylsulfone-3J-disulfonylhydrazide, sulfonylhydrazide compounds such as jinenyloxido-Hiroshi, Hiro'-disulfonylhydrazide.

N, N'-dinitrosopentamethylenetetramine, N,
Nitroso compounds such as N'-dinitroso-N, N'-dimethylterephthalamide, terephthalazide, r-primary? Examples include azide compounds such as butylbenzazide, and inorganic compounds such as small sodium carbonate, 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 foaming agent in the powder molding resin composition (Bl) is 0.2 to 10% of the resin component in the composition (Bl).
The foaming agent is preferably added in a weight range of /A weight, and the amount of the foaming auxiliary agent is preferably the same as or less than the amount of the foaming 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, a method of dispersing the blowing agent and the foaming aid f into a plasticizer and allowing the plasticizer to be absorbed into the vinyl chloride resin; After adhering to the thermoplastic resin at temperature and kneading the composition (
Examples include a method of making rice into husks, or, most simply, a method of adding and mixing a foaming 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 a thermoplastic resin composition (Alt-) and preheated from the outside of the mold to a temperature of /110.2 OC in a heating furnace, hot tube, etc. to adhere the thermoplastic resin composition (A) to the inner surface of the mold,
Next, the mold is inverted and the excess composition (N) that did not adhere to the mold is discharged to form a first resin layer in the mold. The composition (A) is placed in the mold.
) may be performed as /1i'ff1L. The preheating temperature is appropriately selected depending on the desired thickness of the molded product.

-fat king culm- Next, after going through the Al process, a powder molding resin composition containing a pyrolytic foaming agent (filling with Bl) is placed in a slush molding mold in which a pre-formed resin layer has been deposited. ” Aiming at the composition (
A foamable resin layer is formed by applying B) onto a pre-formed resin layer using its tackiness or residual heat from the previous step. If the amount of composition (Bl) is not sufficient, adhesion may be promoted by preheating the mold to a temperature at which the blowing agent does not decompose. - (bl Step 1 In the method of the present invention, after forming the first resin layer and before forming the foamable resin layer, the second resin layer, A third resin layer 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, another resin layer is not laminated on the first resin layer. A method is often used in which the thickness of the first resin layer is controlled and a composition (Bl) is deposited thereon.

The method of the present invention heats the mold in which the first resin layer and the foamable resin layer are attached to melt the first resin layer and the foamable resin layer and decompose the foaming agent contained in the foamable resin layer. The foamable resin layer is foamed by increasing the temperature to a temperature higher than that temperature 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 /4O-2jOC is usually appropriate. For composite foam molded products, after cooling the mold and molded product,
removed from the mold. -(C1 Step 1) 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 lightweight and flexible molded products can be obtained at a low cost. The molded product has no pinholes, scratches, etc. on the surface layer, is strong, has an extremely beautiful appearance, and is fully foamed inside.The molded product in which hard urethane is injected as an aggregate into the interior of the molded product is , has extremely excellent adhesion with urethane.It is still possible to mold products on top of bones 4J such as metals and injection molded products of ABS resin)
Even when coated, it becomes an excellent product.

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

Next, the method of the present invention will be explained in more detail using Examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 Polymerization II)') Diundecyl phthalate (D U
P) A! 3 parts by weight of calcium carbonate, 1 part by weight of Eta-Zn composite liquid stabilizer, 3 parts by weight of epoxidized soybean oil, and pigment (copper-phthalonanine blue)2. Plastisol was prepared by mixing jiii parts. Next, dioctyl phthalate (DOP) is added per ioo weight part of vinyl chloride resin having a degree of polymerization (〒) of about 700.
70 parts by weight, butylbenzyl phthalate (BBP) 70
Parts by weight, 3 parts by weight of Zn-Na liquid foaming stabilizer, parts by weight of azosicabonamide, 1M part by weight of epoxidized soybean oil, parts by weight of acrylic acid cell conditioner, heated and stirred with a Henzoel mixer. After absorption and mixing, 2 io parts by weight of a vinyl chloride emulsion polymerization resin with an average particle diameter of lμ and a degree of polymerization (di) of approximately jθ were added to form a powder molding resin composition (Bl) containing a chemical blowing agent. was prepared.

A center console mold for slush molding of a nickel alloy electroformed skin with a grain pattern was filled with the above sol composition. 2j
After preheating the outside of the triple second mold in an OC gas oven,
Excess sol composition was discharged to form a first resin layer, and then the composition (B) was filled into the mold, and the outside of the mold was reheated for 30 seconds in a 2J'OC gas oven. , the excess composition (B) was discharged from the mold to form a foamable resin layer 1, and then the mold to which two types of resin layers were attached was 1 j
It was held in an OC gear oven for a minute to melt and foam at the same time, resulting in a foam that remained attached to the mold. When the foam was cooled and released from the mold, it was found to be a center console with an extremely beautiful surface and an excellent feel.

Example 2 Vinyl chloride resin with a degree of polymerization (p) of about 100/00
Diundecyl phthalate (1) per tonjii part U
P) J' 0 parts by weight, Ba-Zn liquid composite stabilizer F, 3 parts by weight, epoxidized soybean oil, 3 parts by weight, stearic acid, 3 parts by weight, pigment (polyazo red), 2. heavy weight”
After heating and stirring in a Hennel mixer to absorb and mix, an io heavy portion of vinyl chloride emulsion polymerization resin having a polymerization degree (p) of average particle size/μ of about gro was added to form a composition (A). ) was prepared.

A composition [Bl] containing the chemical blowing agent described in Example 1 was then prepared.

A glove box lid mold for slush molding with a nickel alloy electroformed skin pattern was filled with the above composition (Al), and after preheating the outside of the sand mold in a gas oven of After discharging the composition (N) and subsequently filling the mold with the composition (Bl) and preheating the mold again for 1.2 J' (7 l/-j seconds in a CO gas oven, the excess composition (Bl) was poured into the mold. Then, the mold with the resin layer of (Al (Bl) adhered to it was held in a 2tθC gear oven for ! minutes to melt and foam at the same time, obtaining a foam that remained adhered to the mold. .

When the foam was cooled and released from the mold, it was found to be a glove box lid with an extremely beautiful surface and an excellent feel.

Patent applicant Mitsubishi Monsanto Chemical Vinyl Co., Ltd. Agent (Otsuza ot) Patent attorney Yo Hase - and 1 other person

Claims (1)

[Claims] (Production of a composite foam molded product in a method for manufacturing a composite foam molded product using a slan/yu mold, characterized by passing through the following three steps) j. (1) The thermoplastic 12 (J resin composition (AJ) filled in the gold IGIJ is heated to the mold K (
": After forming the first resin layer, the excess composition fAl is discharged from the mold. (b) The resin layer formed in advance prior to the fbl step A powder molding resin composition (B) containing a pyrolyzable foaming agent is filled into the mold, and the composition [Bl f:
After forming a foamable resin layer by adhering it to the pre-formed resin layer by its adhesiveness or residual heat, excess composition C is
Process of discharging B+ from the mold. (0) 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 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 a plastisol or an organosol. A method for producing a composite foam molded article according to claim 1. (3) Atsushi Town! 2. The method for producing a composite foam molded article according to claim 1, wherein the resin composition (A) is a resin composition for powder molding. (/1) The method for manufacturing a composite foam molded product as set forth in claim 1, item 11, wherein the first resin layer in step fa) and the preformed resin layer in step b) are the same.