WO1993017854A1

WO1993017854A1 - Composite molded product having cushioning properties and method for producing the same

Info

Publication number: WO1993017854A1
Application number: PCT/JP1993/000290
Authority: WO
Inventors: Toshinori Koseki; Kunio Maeda; Syoichi Kanno
Original assignee: Asahi Kasei Kogyo Kabushiki Kaisha; Toyota Jidosha Kabushiki Kaisha; Kabushiki Kaisha Kobe Seiko Sho; Mitsubishi Petrochemical Co., Ltd.
Priority date: 1992-03-10
Filing date: 1993-03-10
Publication date: 1993-09-16
Also published as: DE4390938C2; DE4390938T1; GB9322239D0; KR0124927B1; GB2273457B; DE4390938C3; CA2102608C; TW252074B; GB2273457A; CA2102608A1

Abstract

A composite molded product having cushioning properties in which a cushioning material having a surface material is integrally provided on a hard base material and a method for producing the composite molded product in a simple process having less producing steps. A hard resin molded product is set in a metallic mold, and an expandable rubber-like elastic body is injected, and then the metallic mold is expanded so that expansion of the rubber-like elastic body can be effected, whereby the expanded rubber-like elastic body and the skin layer thereof constitute a cushioning material and a surface material, respectively, and the formation of those materials and integration of those materials with the hard base material as a hard resin molded product can be performed in succession in one metallic mold. Thus, production is made simple and labor and production cost can be reduced.

Description

Fine cushioning composite molded article and its manufacturing method <Technical field>

The present invention relates to a cushioning composite molded article comprising a hard base material, a cushion material integrally provided on the hard base material and covered with a surface material, and a manufacturing method thereof. It is about methods. More specifically, it has a hard base material to obtain a certain strength, and a cushion material covered with a surface material to obtain an excellent appearance and soft feel. Automotive interior materials (instrument panels, door panels, seating panels, steering wheels, handles, etc.), furniture (chair seats, etc.), The present invention relates to a cushion-type composite molded product used for parts and products such as miscellaneous goods (shoes, slippers, etc.) and a method for producing the same.

Conventionally, the following methods have been known as methods for producing cushioning composite molded articles.

(1) Vacuum forming semi-rigid vinyl chloride sheet using semi-rigid vinyl chloride resin, or slush molding semi-rigid vinyl chloride resin to form surface material A hard base material is created by injection molding a lens, AS resin, ABS resin, etc., and the surface material and the hard base material are placed in a mold, and a foamable poly resin is injected and foamed between the two. Let To make cushion material.

(2) A hard material obtained by separately injection molding a laminate of surface material and cushioning material obtained by bonding a semi-rigid vinyl chloride sheet and a cross-linked foamed polypropylene sheet with an adhesive. A method in which it is adhered to a substrate by vacuum molding.

(3) A laminate of surface material and cushioning material obtained by bonding a semi-rigid vinyl chloride sheet and a cross-linked foamed polypropylene sheet with an adhesive is placed in a mold. A method in which a hard resin is injected into the lower mold side of the mold to form a hard base material, and integrated with a laminate of the surface material and the cushioning material.

However, the above-mentioned conventional manufacturing methods each include a non-foamed surface material, a cushion material obtained by foaming an expandable rubber-like elastic material, and a hard base material which is a hard resin molded product. However, since these are separately molded and integrated into a product, there are problems in that the number of manufacturing steps is large, it is troublesome, and the manufacturing cost is high.

In order to solve these problems, many methods have been devised, but all have drawbacks.

Japanese Patent Application Laid-Open No. H11-2494916 discloses that a thermoplastic elastomer material containing a foaming agent is inserted into a mold after a resin insert made of polyolefin is inserted into a mold, and a product carrier is provided. A non-foamed skin is charged into the cavity by charging an amount smaller than the capacity of the product (hereinafter referred to as a short shot) and then foaming it in a mold. At the same time, the soft resin-coated portion is adhered or heat-sealed to the insert through the skin. Then, a method for producing a soft resin molded product is described. (Insert short shot method)

However, with this method, it is not possible to mold a molded article in which the state of the mold surface is accurately transferred with a small thickness and a high expansion ratio. The surface of the molded article produced by this method becomes a markedly rough surface peculiar to the surface of the foam molded article molded by the short shot method. For example, a molded product having a surface similar to natural leather, which can be obtained only by accurately transferring a surface pattern, cannot be formed.

In Japanese Patent Application Laid-Open No. 49-11067, a strength retainer is preliminarily charged into an injection molding mold having a cavity capable of increasing the volume while holding a molten resin therein. Then, after injecting the foamable polyrefin resin thermoplasticized into the mold cavity, the volume of the cavity is increased to foam the polyrefin. A method for producing a laminated structure having a polyolefin foam layer is described.

(Insert type gap expansion method)

However, since the polyolefin does not have good rubber-like elasticity like a saturated styrenic rubber-like elastic material, it cannot be used to foam the polyolefin. According to this method, a high-quality cushioning composite molded article having a good feeling with a foot, which is an object of the present invention, cannot be obtained.

Japanese Unexamined Patent Publication No. Sho 63-32-27331 discloses that in a soft resin injection molded product comprising a resin insert and a soft resin coating portion, the resin insert is a polyolefin resin. And a soft tree Styrene based resin with a hardness of 10 to 0.50 for hardness (JISK6301: A type) and compression set (JISK630: 70 ° CX22h) It describes a soft resin injection-molded product that is a thermoplastic elastomer and has a soft resin coating portion having a thickness of 0.5 mm or more. (Insert and non-foam molded products)

This molded product is molded by a general insert / non-foam injection molding method. With the general insert and non-foam injection molding methods, it is possible to form a molded product that is thin and accurately transfers the mold surface pattern. However, the softness that is the object of the present invention provides a good feel. High quality cushioning composite molded products cannot be obtained.

An object of the present invention is to form a surface material made of a non-foamed flexible rubber elastic body, a cushion material formed by foaming a rubbery elastic body, and a hard base material of a hard resin molded product. It is an object of the present invention to provide high-quality cushioning-type composite molded products. Another object of the present invention is to provide a method for producing the composite molded article in a small number of steps and at low cost. More specifically, a hard resin molded product molded in advance is mounted as a hard substrate in a mold having a larger gap than the hard resin molded product, and then a foamable rubber-like elastic body is placed in the gap. After injection into the mold, the inside of the mold is shot and a foamable rubber-like elastic layer is integrally formed on the hard base material. Then, the inside of the mold is enlarged to expand the foam-like rubber-like elastic body. By foaming the layer, the rigid substrate A surface material having a good appearance and feel similar to, for example, natural leather, and a cushion material covered with the surface material, provided on the hard base material. Cushioning Either make it possible to manufacture composite molded products with a small number of manufacturing steps and low manufacturing costs (insertion and mold cavity enlargement method), or use hard resin in the mold. After injection, the inside of the mold is completely filled to obtain a hard resin molded product as a hard base material, and after cooling, the inside of the mold is enlarged. After injecting the foamable rubber-like elastic body to completely fill the inside of the mold and integrally form the foamable rubber-like elastic layer on the hard substrate, the inside of the mold is further expanded to expand the foam. By foaming the rubber-like elastic body layer, a hard base material and a surface having a good appearance and feel similar to, for example, natural leather A cushion-type composite molded product comprising a cushion material covered with the same surface material and provided on the hard substrate, with a reduced number of manufacturing steps and The aim is to make it possible to manufacture at low manufacturing cost (two-layer molding and mold cavity enlargement method).

In other words,

A hard base material previously molded into a desired shape is mounted in a mold having a larger gap than the hard base material or a hard base material is injected into a mold having a desired shape by injecting a hard resin. After forming, the inside of the mold is expanded to have voids,

Next, foamable rubber-like elastic material is injected into these voids and covered with a surface material as a skin layer that accurately transfers the mold surface pattern onto a hard substrate. Body layer Form

Further, the inside of the mold is enlarged to foam the foamable rubber-like elastic material layer to form the cushion material covered with the surface material.

It is composed of a hard base material and a cushion material integrally formed on the base material, and the surface of the cushion material has a mold surface pattern accurately transferred thereon, The present invention relates to a method for producing a cushioning composite molded article having an excellent appearance and a soft feel, and a cushioning composite molded article produced by the production method.

<Brief description of drawings> ''

FIG. 1 is an explanatory view showing the procedure for the first embodiment of the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view of the cushioning composite molded product according to the present application.

FIG. 3 is an explanatory diagram showing a procedure for a second embodiment of the manufacturing method of the present invention.

The symbols in the drawings have the following meanings.

1 Hard resin molded product

2, 2 'mold

2 a, 2 a 'fixed type

2 b mobile type

3 Rubbery elastic body

4 Skin layer

5 Cushioned composite molded products 6 Surface material

7 Foam elastic

8 cushion materials.

9 Hard substrate

BEST MODE FOR CARRYING OUT THE INVENTION>

The present invention relates to the above-mentioned production method (insert mold void enlarging method and two-layer molding, mold void enlarging method) and a molded product produced by the production method, wherein a specific rubber-like elastic material is used. By setting the molding conditions (mold inner surface temperature, time from injection completion to start of moving mold retreat, etc.) well, high-pressure gas is injected in advance into the cavity in the mold (counter Without using the danger method called cushioning method) A cushioning material covered with a hard base material and a surface material with good appearance and feel similar to natural leather, for example. It is based on the finding that high-quality cushioning-type composite molded articles made of can be manufactured with few manufacturing steps and low manufacturing costs.

The thermoplastic rubber-like elastic body in the present invention constitutes a surface material and a cushion material. As this rubber-like elastic body, a saturated styrene-based rubber-like elastic body is used. The average molecular weight based on the GPC method is more than 30,000 and up to 70,000 or less, as a saturated styrene rubber-like elastic material. A saturated styrene rubber-like elastic material having a hardness of more than 50 and less than 100 is preferably used. This saturated styrenic rubber-like elastic material is a saturated styrenic rubber. It may be a len-butadiene rubber-like elastic material or a saturated styrene-soprene rubber-like elastic material.

If the average molecular weight of the saturated styrenic rubber-like elastic material exceeds 70,000, it does not foam well by the method of the present invention. In addition, if the average molecular weight of the saturated styrene rubber-like elastic material is less than 30,000, the method of the present invention may break the cell wall at the stage of foaming and form open cells. However, large bubbles are formed, or cracks or cavities are formed inside, so that high-quality cushioning composite moldings cannot be formed.

The saturated styrene rubber-like elastic material is covered with a surface material having a good appearance and feel similar to natural leather, for example, if the hardness exceeds 100, based on JISK631. It is not possible to obtain a flexible, high-quality cushioning-type composite molded product made of a cushioned material. Further, the saturated styrene rubber-like elastic material can be foamed well by the method of the present invention even if the A hardness is 50 or less based on JISK631, but the molded cushion is The water-soluble composite molded product has a sticky surface and is remarkably flexible, so that a high-quality cushioning composite molded product cannot be obtained.

The saturated type rubber-based elastic body may be used alone, or may be a compound with another rubber-like elastic body, a synthetic resin, a filler or the like. Particularly when the saturated styrenic rubber-like elastic material is a compound of the above-mentioned specific saturated styrenic rubber-like elastic material and polyolefin. A high quality cushioning composite molded product can be easily molded. The low-density polystyrene is used as a polyrefin which can be used for the compound of the specific saturated styrenic rubber-like elastic material and the polyrefin. , Polyolefins such as linear low density polyethylene, high density polyethylene, polypropylene, polybutene, ethylene and other orthoolefins Ethylene copolymers with ethylene monomers, ethylene copolymers with ethylene and other vinyl monomers', propylene and other olefinic copolymers Propylene copolymers with monomers, ethylene ■ olefin rubbers such as propylene rubbers.

In particular, the saturated styrene-based rubber-like elastic body is a combination of the specific saturated styrene-based rubber-like elastic body and a polyrefin. If it is a hand, the hardness of this component and the hand must be in the range of more than 50 and less than 100 in accordance with JIS.K6301. If this is not the case, the method of the present invention provides a flexible, high-quality material consisting of a cushion material covered with a surface material that has a good appearance and feel similar to natural leather, for example. A cushioned composite molded product cannot be obtained.

In addition, the melt viscosity of this compound at the temperature at the time of injection in the method of the present invention is not less than 300 poise and not more than 3 poise at a shear rate of 1,000 oz. It must be within the range of 5, 0 0 poise or more and 5 0, 0 0 poise or less. This If it is outside of the range, the method of the present invention provides a high-quality cushioning made of a cushioning material covered with a surface material having a good appearance and feel similar to, for example, natural leather. Unable to obtain composite molded product. In particular, when the melt viscosity at a shear rate of 1,000 O Zsec exceeds 3,500 O poise and the melt viscosity at a shear rate of 10,0 O sec exceeds 50,00.0 poise, the method of the present invention uses The compound does not form well and does not foam.

Further, the present invention will be described in detail.

In the first embodiment of the insert mold cavity enlargement method and the second embodiment of the two-layer molding mold cavity enlargement method for producing the composite molded article of the present invention, the most important steps are the surface material and the cladding. The most preferable average molecular weight of the foamable rubber-like elastic material in the step of forming the cushioning material is 40,000 or more and 60,000 or less. A thermoplastic rubber-like elastic material having a relatively large molecular weight and a thermoplastic rubber-like elastic material having a relatively small molecular weight are mixed so that the average molecular weight is not less than 40,000 and not more than 60,000. Is also a preferred method. By combining the features of a thermoplastic rubber-like elastic material with a relatively large molecular weight and the features of a thermoplastic rubber-like elastic material with a relatively small molecular weight, the disadvantages of both can be eliminated. When the average molecular weight of the thermoplastic rubber-like elastic body increases, the melt viscosity of the thermoplastic rubber-like elastic body at the time of molding increases, so that it becomes difficult to mold a thin large-sized molded product or foam. However, the strength and heat resistance of the molded product are improved. on the other hand, When the average molecular weight of the thermoplastic rubber-like elastic material is small, the melt viscosity of the thermoplastic rubber-like elastic material at the time of molding is low, so that a thin large-sized molded product can be easily molded or foamed easily. As a result, the strength and heat resistance of the molded product decrease. Therefore, the optimal average molecular weight of the thermoplastic rubber-like elastic material should be selected within the range of 40,000 or more and 60,000 or less depending on the shape, dimensions and required characteristics of the molded product. Most preferred.

In the method of the present invention, the thickness of the surface material and the expansion ratio of the cushion material can be arbitrarily set by appropriately setting the molding conditions, so that the thickness of the surface material is set to be thin. When the foaming ratio of the cushioning material is set to a high value, the saturated type rubber-based elastic material has a relatively high A-hardness based on JISK 6301. However, it is possible to obtain flexible, high-quality cushioning composite molded products. However, if the A-hardness based on JISK 6301 exceeds 100, the formed composite cushioning product is too hard, and the flexible and high-quality cutout of the object of the present invention is obtained. It is not possible to obtain a shocking composite molded product. In addition, by setting the thickness of the surface material to be large and the foaming ratio of the cushion material to be low, the saturated S-styrene rubber-like elastic material based on JISK 6301 Even if the hardness is relatively low, it is possible to obtain a flexible, high-quality cushioning composite molded product. However, a cushion-type composite molded product having an A hardness of 50 or less based on JISK 6301 has a sticky surface, is extremely flexible, High quality cushioning compound for the purpose of It is not a molded product.

In the process of forming the surface material and the cushion layer, the injection molding conditions of the foamable rubber-like elastic body include the temperature of the molten rubber-like elastic body in the injection cylinder and the start of injection. Pressure (back pressure) of the molten rubber-like elastic body in the injection cylinder, pressure (injection pressure) of the molten rubber-like elastic body in the injection cylinder during injection, mold inner surface temperature, Mold thermal conductivity, time from injection start to injection completion (injection time), time from injection completion to mobile mold retraction start (primary mold opening start) (mould opening start time), mobile mold retraction start It is most important to properly set the time until the retraction is completed (required mold opening time) and the time from the completion of the retraction of the movable mold to the start of mold opening (start of secondary mold opening) (cooling time).

The temperature of the molten rubber-like elastic body in the injection cylinder is set in the range of 190 to 270 ° C.

Pressure in the molten rubbery elastomer into an injection Shi Li Nda until the start of injection (back pressure) is set in the range of 1 0 kg zone ^{cm 2 ~ 5 0 0 kg /} cm 2. The gas for foaming generated by decomposition of the chemical foaming agent must be completely dissolved in the molten rubber-like elastic body, and the pressure must be set so that it completely melts. Usually, it is more preferable to set within the range of ²⁰ kg / cm ² to 100 kg / cm ² .

The pressure (injection pressure) of the molten rubber-like elastic body in the injection cylinder at the time of injection is set within the range of 100 kgZcm ² to 1,500 kg / cm ² . Usually ^{3 0 0 kg cm 2 ~ 1} , More preferably, it is set within the range of 0.0 kg / cm ² .

The mold inner surface temperature is set within the range of 0 to 80 ° C. Normally, it is sufficient to set a value in the range of 10 to 30.However, when a rubber-like elastic material with a large molecular weight is used or a rubber-like elastic compound with a high melt viscosity is used In this case, it is preferable to set a relatively high temperature. If the mold inner surface temperature is set to a relatively high temperature, set a longer time from the completion of the injection to the start of the retraction of the movable mold (start of opening the primary mold), or the time from the start of the retraction of the movable mold to the completion of the retraction. It is necessary to set a long time.

The material of the mold is not particularly limited, and generally used metals can be preferably used. In order to enhance the transferability of the mold surface pattern, the surface of the mold is coated with a material with high heat insulation, or a material with low thermal conductivity such as resin mold or ceramic mold is used. Molds can also be used. When the surface of the mold is covered with a material with high heat insulation, or when using a mold with a low thermal conductivity such as a resin mold or a ceramic mold, the movable mold recedes from the completion of injection. It is necessary to set a long time until the start (opening of the primary mold) and a long time from the start of the mobile retraction to the completion of the retraction. The mold surface directly in contact with the surface material may be provided so that a leather-like pattern or other patterns can be transferred to the surface material depending on the use of the composite molded article.

Time from injection start to injection completion (injection time :) is complete Must be set as short as possible. Normally, it is preferable to set it within 5 seconds, more preferably set it within 1 second, and most preferably set it within 0.5 second. If the time from the start of injection to the end of injection is too long, foaming will start by the end of injection, and it will not be possible to mold good molded products. If the size of the molded product is large, it may be difficult to set it too short, but it must be set as short as possible.

It is very important to set the time (injection start time) from the completion of injection to the start of retraction of the movable mold (start of primary mold opening), and it must be set as short as possible. Usually, it is preferable to set it within 30 seconds, and it is even more preferable to set it within 5 seconds. It is often preferable to set it within one second. By setting this time short, it is possible to reduce the thickness of the surface material, and by setting this time long, it is possible to increase the thickness of the surface material. If the rubber hardness of the rubber-like elastic material is relatively high based on JISK 6301, good quality can be achieved by setting this time relatively short to reduce the thickness of the surface material. Can be molded. If the rubber-like elastic material has a relatively low A-hardness based on JISK 6301, set this time to a relatively long time and increase the thickness of the surface material to obtain good quality molding. Products can be molded. If this time is too long, the rubber-like elastic body does not foam, and if it is too short, a good surface material is not formed. The setting of the time from the start of the mobile retraction to the completion of the retraction (required opening time, time) is very important and needs to be set appropriately. Usually, it is preferable to set it within 30 seconds. By setting this time short, the thickness of the surface material can be reduced, and by setting this time long, the thickness of the surface material can be reduced. Can be made thicker. If the rubber-like elastic material has a relatively high A-hardness based on JISK 6301, it is good to set this time relatively short to reduce the thickness of the surface material. High quality molded products can be molded. If the rubber-like elastic body has a relatively low A-hardness based on JISK 6301, good results can be obtained by setting this time relatively long and increasing the thickness of the surface material. High quality molded products can be molded. If the time is too long, the rubber-like elastic body does not foam, and if it is too short, a good surface material is not formed.

It is preferable to set a longer time (cooling time) from the completion of retraction of the movable mold to the start of mold opening (start of secondary mold opening). Normally, it is preferable to set it to 30 seconds or more. If this time is too short, foaming will continue until after the mold opening starts (secondary mold opening starts), and it may not be possible to mold molded products of good quality.

The rubber-like elastic body used in the present invention is foamable and contains a foaming agent. The foaming agent is not particularly limited as long as it is capable of foaming a rubber-like elastic body by injection molding. For example, azo compounds such as azodicarbonamide, N, Organic chemical blowing agents such as N'-nitro compounds, such as N'-nitronitropentamethylentramine, and inorganic chemical blowing such as sodium carbonate and sodium bicarbonate. Agents can be used. It is also a good method to use an organic chemical blowing agent and an inorganic chemical blowing agent together.

When foaming is performed at relatively high temperatures, P, .P '— oxybisbenzenesulfonylsemicarbazide, p — toluenesulfonylsemicarbazide, trihydrazinotriazine, Compounds such as barium abdicarboxylate can also be used, but in general, abdicarbonamide amide / sodium bicarbonate is preferred.

In addition, it goes without saying that these foaming agents may contain various foaming assistants.

In the present invention, the hard resin constituting the insert base material or the hard base material formed by two-layer molding may be a hard thermoplastic resin that can be injection-molded. Polyolefin resins such as polyethylene, polypropylene, etc., polystyrene, acrylonitrile / styrene copolymer resin, acrylonitrile Polystyrene-based resin such as non-butadiene-styrene copolymer resin, modified polyphenylene ether-based resin, Polyamide 6, Polyamide 66, etc. Polyester resins such as amide resin, polyethylene terephthalate resin, polyester terephthalate resin, polyoxymethylene homopolymer, poly Polyoxymethylene copolymers such as oxymethylene copolymer Butter, port re-methylation Methacrylate resin can be used.

The hard resin to be used may be one kind of hard resin, but may be a blend of a plurality of kinds of hard resins, or may be made of another synthetic resin, a rubber-like elastic material, a filler, a reinforcing material, or the like. It may be a compound.

The hard resin preferably has a small specific gravity in order to reduce the weight of the obtained cushioning composite molded article. From this viewpoint, it is preferable to use a polyolefin resin or a polyolefin resin. Styrene resin is preferred.

The rubber-like elastic body constituting the above-mentioned surface material and cushion material and the hard resin constituting the above-mentioned hard base material are recycled together without separating the rubber-like elastic body from the hard resin. It is preferable that the materials are compatible with each other and, if possible, of the same kind so that they can be mixed. However, in general, even if a rubber-like elastic body and a hard resin that are not compatible with each other are used, it is possible to recycle them by using a compatibilizer at the time of recycling. is there.

Next, the procedure of the present invention will be described.

(1) The invention of the insert-type void enlarging method (first embodiment)

The procedure of the insert-type void enlarging method will be described with reference to Fig. 1.

The injection molding equipment used in this insert mold gap enlarging method can be the most common injection molding equipment having one injection machine. First, as shown in (a), the hard resin molded product 1 is mounted in the mold 2. This hard resin molded article 1 constitutes the hard base material 9 of the cushioning composite molded article 5 shown in FIG. 2, and is formed as a hard base material 9 by a molding method using a hard resin. What is necessary is just to be molded into the required shape. Generally, it is an injection molded product, but it may be a compressed air molded product, a vacuum molded product, or the like.

The mounting of the hard resin molded article 1 in the mold 2 is performed along the fixed mold 2a or the movable mold 2b, and is performed along the movable mold 2b in the drawing.

Next, as shown in (b), a foamable rubber-like elastic body 3 is injected into a cavity in the mold 2 on which the hard resin molded article 1 is mounted, to completely fill the cavity of the mold 2. I do. That is, the foamable rubber elastic body 3 is fully shot.

The thickness of the cavity inside the mold 2 filled with the foamable rubber-like elastic body 3 is preferably in the range of 0.5 to 4 mm, more preferably in the range of 1 to 3 mm. It is in that. If the thickness is too small, it becomes difficult to foam the foamable rubber elastic body 3. If the thickness is too large, good foaming can be achieved, but the weight of the molded article is unnecessarily heavy and uneconomical, which is not preferable. Further, in order to uniformly foam the foamable rubber-like elastic body 3 as a whole, it is preferable that the thickness of the inside of the mold 2 filled with the foamable rubber-like elastic body 3 is uniform. However, depending on the intended use of the obtained cushioning composite molded article 5 (see Fig. 2), this empty space may be intentionally used. In some cases, it may be desirable to vary the thickness of the gap to intentionally cause uneven foaming.

What is important in this step (b) is to shoot the foamable rubber-like elastic body 3 into the void. When this shot is performed, the rubber-like elastic body 3 has foaming properties, but foaming is suppressed by the pressure caused by the injection, so that almost no foaming occurs at this stage. (In addition, the foamable rubber-like elastic body 3 comes into close contact with the inner surface of the mold 2 due to the full shot, and the foamable rubber-like elastic body 3 comes into contact with the inner surface of the mold 2. The surface portion of the body 3 is cooled and hardly foams even in the subsequent stages to form a so-called skin layer 4 (non-foamed surface material). Is the surface material 6 of the cushioning composite molded product 5 shown in FIG. 2, and is formed in a substantially unfoamed state in close contact with the inner surface of the mold 2. Therefore, the surface pattern of the mold is transferred to the mold pattern accurately and has a good surface condition.

On the other hand, when the injection of the foamable rubber-like elastic body 3 in an insufficient amount to fill the cavity inside the mold 2 is performed instead of the above-described shot into the mold cavity-( At this stage, foaming of the foamable rubber-like elastic body 3 occurs. The foamable rubber-like elastic body 3 foams and expands in volume, so that it closely adheres to the inner surface of the mold 2 and cools the surface.However, the surface obtained in this way after foaming Since it is a cooled surface, it has a rough surface and has the practical appearance and feel of natural leather, for example, which is the object of the present invention. No surface material is formed.

After completely filling the mold cavity as described above, the injection E force is released and the movable mold 2 b is moved when the foamable rubber-like elastic body 3 is in a foamable state. Then, the inside of the mold 2 is enlarged. As shown in (c), the expansion inside the mold 2 is performed without separating the fixed mold 2a and the movable mold 2b and keeping the mold 2 in the unreleased state (core sealed type). However, as shown in (d), the fixed type 2a and the movable type 2b may be separated and the mold 2 may be released (core release type). Also, a movable block is provided in the fixed mold 2a or a part of the movable mold 2b without moving the entire movable mold 2b, and the mold 2 is moved by moving the block. The inside may be partially enlarged.

As a result, as shown in (e) and (f), the foamable rubber-like elastic body 3 foams to form a foamed elastic body 7. This foamed elastic body 7 constitutes the cushioning material 8 of the cushioning-type composite molded article 5 shown in FIG.

In the case of the core release type shown in (d), the foamable rubber elastic body 3 is free foamed with its surface away from the mold 2, so that the surface becomes a smooth curved surface and relatively high foaming. This gives a multiple of foam 7. On the other hand, in the case of the closed core type (c), by adjusting the amount of movement of the movable mold 2b, foaming can be performed while controlling the thickness of the foamed elastic body 7 obtained.

In the step (b), the skin layer 4 (surface material) having a good surface condition is obtained, and the skin layer 4 (c) or (d) to (e) or In order to obtain a good foaming state of the foamable rubber-like elastic body 3 at the stage (f), the inner surface temperature of the mold 2 at the stage (c) or (d) from the stage (b) is determined. It is necessary to set it appropriately.

The set temperature of the inner surface of the mold 2 from the step (b) to the step (c) or (d) differs depending on the type of the rubber-like elastic body 3 used. What is necessary is just to set within the range of the temperature which can fully solidify 3, and usually about room temperature is enough. It is also effective to coat the inner surface of the mold 2 with a heat insulating layer made of a material with low thermal conductivity, if necessary, or to configure the entire mold 2 with a material with low thermal conductivity. .

In some cases, it is also effective to heat the mold 2 within a temperature range in which the rubber-like elastic body 3 can be sufficiently solidified. This is an example of a preferred method in which the heating of the mold 2 is performed only on the inner surface of the mold 2 by a high-frequency induction heating method or the like.

The time from the completion of the injection of the foamable rubber-like elastic body 3 into the mold 2 to the start of the retreat of the movable mold 2b (mold opening start time) is determined by the foaming elasticity at the stage (c) or (d). In order to obtain a good foaming state of the rubber-like elastic body 3, the type of the rubber-like elastic body 3, the inner surface temperature of the mold 2 (the temperature of the rubber-like elastic body 3), and the like (preferably adjusted accordingly). New

For example, when the rubber-like elastic body 3 to be used is relatively hard, the thicker the skin layer 4 is, the more difficult it is to foam even if the movable mold 2b is retracted. Temperature relatively It is preferable that the movable mold 2b be retracted at an early stage after the injection of the foamable rubber-like elastic body 3 so that it can be maintained at a high level. When the rubber-like elastic body 3 to be used is relatively soft, the movable rubber 2 is injected after the foamable rubber-like elastic body 3 is injected in order to promote the formation of the skin layer 4 having a good surface condition. It is preferred that the mobile 2.b be retracted after a relatively long time before the retraction of b is started.

The time from the start of retreat to the end of retreat of mobile type 2 b is

It is important to obtain a good foaming state of the foamable rubber-like elastic body 3 in the step (c) or (d), and the same as the time from the completion of injection to the start of retreat of the movable mold 2b, It is preferable to make appropriate adjustments.

As described above, the foamed rubber-like elastic body 3 is foamed into a foamed elastic body 7 having a skin layer 4 and then sufficiently cooled and taken out of the mold 2, as shown in FIG. Thus, the cushioning composite molded article 5 in which the cushioning material 8 having the surface material 6 is integrally provided on the hard base material 9 can be obtained.

(2) Invention of Two-Layer Molding · Mold Void Enlargement Method (Second Aspect)

The procedure of the two-layer molding and mold gap enlarging method will be described with reference to FIG.

The injection molding apparatus used in the invention of the two-layer molding / mold gap enlarging method is an injection molding apparatus having two or more injection machines, generally called a two-color molding machine or a multicolor molding machine. is there.

First, as shown in (a), a hard resin is injected into a mold 2 ′ composed of a fixed mold 2 a ′ and a movable mold 2 b to form a hard resin molded product 1. The molding of the hard resin molded product 1 may be performed until the hard resin injected into the mold 2 ′ is sufficiently cooled, but the cooling is performed so as not to be deformed in the next step (b). You may leave it in the state.

Next, as shown in (b), the movable mold 2 b is retracted and separated from the fixed mold 2 a ′, and combined with the new fixed mold 2 a, thereby expanding the inside of the mold 2. Then, a gap is formed in the mold 2. The enlargement in the mold 2 can be performed as the enlargement in the mold 2 'shown in (a). For example, a movable block is provided in a part of the fixed mold 2a 'or the movable mold 2b, and the inside of the mold 2' can be partially enlarged by moving the block D. And it is good. Alternatively, the inside of the mold 2 ′ may be enlarged by moving the movable mold 2 b within a range where the mold 2 ′ shown in (a) is not released. This step (b) corresponds to the state shown in Fig. 1 (a), and the subsequent steps (c) to (g) are steps in Figs. 1 (b) to (f). It is similar to the stage described.

In the case of the insert-cavity enlarging method described above, a hard resin molded product 1 serving as a hard base material 9 is separately formed in advance, and a surface material 6 and a cushion material 8 are formed and a cup material is formed. The molding material 8 and the hard base material 9 are integrated by one mold 2. On the other hand, the two-layer molding and mold void enlarging method use a hard substrate 9 It is possible to remove the hard resin molded product 1 from the mold 2 ′ without removing it from the mold 2 ′. And it is easy to improve the joining state of both. Further, for the same reason, when the foamable rubber-like elastic body 3 is injected, the thickness of the skin layer 4 formed at a position in contact with the hard resin molded product 1 can be made extremely thin. .

[Example] and [Comparative Example]

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but it is needless to say that the present invention is not limited by the Examples and Comparative Examples.

The materials, equipment and molding procedure used here are as follows.

(1) Material

Hard resin

PP: ^ 1? 1 = 88/1 01 ^ 11 in 230 based on ASTM 0 1 2 3 8, Density based on ^ 1 D1505 in 8 3 = 0.90 g Z Po Li professional Pile emissions of cm ²

GPP: MFR at 230 based on ASTM 0 1 2 3 8 = 7 g Z 10 min, density based on ASTM D 150 5 = glass fiber reinforced with 1.1 2 g / cm ² Polypropylene

Rubber-like elastic body

SB 1: Average molecular weight based on GPC method 50, 000, A hardness based on JISK 631, 67, styrene content 20% by weight of saturated styrene-butadiene rubber-like rubber

SB2: Saturated styrene-butadiene system with average molecular weight of 40,000 based on GPC method, A hardness of 84 based on JISK631, styrene content of 30% by weight Rubber-like elastic body

SB 3 ··· Saturated styrene with average molecular weight of 500,000 based on GPC method, A hardness of 67 based on JISK 631, and styrene content of 20% by weight 60 parts by weight of a gen-based rubber-like elastic material with an average molecular weight of 70,000 based on the GPC method, an A hardness of 67 based on JISK 631, and a styrene content of 20% by weight 20 parts by weight of saturated styrene-butadiene rubber-like elastic material and MI at 190 ° C based on ASTMD 1238 = 19 g Zl 0 min, ASTM D 1 5 0 5 based rather density zero. 9 3 and g / cm ² of the linear low density Dopo re ethylene les down 5 parts by weight, the aS TM D 1 2 3 8 based Dzu rather 2 3 0 ° C MFR = 4 O g Z l 0 min, density based on ASTM D 1505 = 0.90 g / cm ² Polypropylene 20 parts by weight, JISK 6301 Melt viscosity at 740, 230 ° C is 1,800 poise at a shear rate of 1,000 / sec and at a shear rate of 10,800 / sec. 1 8 0 0 0 a poise, co down Bruno with saturated styrene-les down one pig diene emissions based rubber 厶状 elastic body and port the Rio les off fin, ° © down de

Foaming agent BA 1: Abuji force Norebon amide foaming agent

B A 2: Sodium bicarbonate foaming agent

(2) Molding equipment

Core rotation type 2 color different material injection molding machine

(3) Molded product dimensions and outer shape (when not foamed)

Box shape with a radiation of 74 mni, length of 100 mm and height of 10 mm. However, the thickness of the hard resin-filled part (hard resin molded product) is 2 mm, and the thickness of the foamable rubber-like elastic body is 3 mm or 2 mra.

(4) Molding procedure

Granular hard resin is charged into the resin supply port of the first injection machine of the molding machine, and a mixture of the granular rubber elastic body and the powdery foaming agent is charged into the resin supply port of the second injection machine. throw into.

Using the first injection machine, the hard resin is injected into a mold having a cavity corresponding to the hard resin molded product, and the hard resin molded product is formed.

When the hard resin molded product is removed and cooled to the point where it can be taken out, the movable mold of the mold is retracted, and the movable mold is rotated and connected to the fixed mold of the second injection machine to form the foam. A void is formed to eject the rubber-like elastic material. Then, the foamable rubber-like elastic body is injected into the space in the mold using the second injection machine.

When the surface layer of the injected foamable rubber-like elastic body is solidified and the inside is in a molten state and can be foamed, the movable mold is retracted to foam the inside of the rubber-like elastic body. The expansion inside the mold due to the retreat of the movable mold is performed by the core release type in Example 1, Comparative Example 1, Example 2, and Comparative Example 2, and the core density in Example 3 is used. It is closed.

When the foamed elastic body formed by foaming the foamable rubber-like elastic body is sufficiently cooled, the molded cushioning composite molded article is removed from the mold.

Example 1

The expansion inside the mold due to the retraction of the movable mold was of the core release type, and molding was performed by changing the type of hard resin, the type of rubber-like elastic body, and the type of foaming agent. The injection of foamable rubber-like elastic material was all shot. The conditions and results are shown in Table 1. Even if the type of the hard resin was changed, a cushion-like composite molded article having excellent appearance and appropriate cushioning properties could be formed.

Also, even if the type of the rubber-like elastic body was changed, it was possible to mold a cushioning composite molded article having an excellent appearance and an appropriate cushioning property. However, the molding state changes depending on the type of the rubber-like elastic body, and the cushioning property of the obtained cushioning composite elastic body particularly depends on the hardness of the rubber-like elastic body. changed.

Furthermore, even when the type of the foaming agent was changed, all of them could be used favorably. '

Comparative Example 1

Table 1 shows the conditions and results of molding a composite composite article with the injection of a foamable rubber-like elastic body as a short shot.

A good molded product could not be molded. Example 2

The expansion inside the mold due to the retraction of the movable mold was a core release type, and molding was performed by changing the amount of foaming agent added. In addition, all injections of foamable rubber-like elastic material were made full shot. Table 2 shows the conditions and results.

The cushioning properties of the obtained cushion-like composite molded article changed depending on the amount of the foaming agent added.

The expansion inside the mold due to the retraction of the movable mold is a core release type, and molding is performed by changing the mold temperature and the time from the completion of injection of the rubbery elastic body to the start of retraction of the movable mold (mold opening start time). I went. All injections of the foaming rubber-like elastic material were shot. Table 2 shows the conditions and results.

Changing the mold temperature changed the appropriate mold opening start time. In other words, when the mold temperature was increased, a good cushioning composite molded article could be obtained even when the mold opening start time was lengthened.

Comparative Example 2

Molding was carried out with the mold opening start time changed significantly.

Exceeding the appropriate mold opening start time range, good molded products could not be molded.

Example 3

The inside of the mold due to the retraction of the movable mold is a core-sealed type, and molding is performed by changing the type of foaming agent, the thickness of the foamable rubber-like elastic material filling portion, and the type of rubber-like elastic material. went. In addition, all injection of foamable rubber-like elastic material was made full shot. conditions Table 3 shows the results.

In the case of the closed core type, good foaming can be achieved even if the type of foaming agent is changed, the thickness of the foamed rubber-like elastic material filling portion is changed, or the type of rubber-like elastic material is changed. I was able to get the status.

The evaluation of the physical properties of the molded article is based on the following criteria.

Foaming condition: good: A non-foamed surface material with a constant thickness is formed uniformly on the surface of the molded product, and a cushion material with a number of fine closed cells is evenly formed inside. Bad, Bad: Foamed state of molded product different from above.

Good appearance: The mold surface pattern is accurately transferred to the molded product surface.

Poor: State in which a pattern different from the mold surface pattern, such as unevenness or flow pattern, is formed on the molded product surface.

Good feel: a surface material composed of smooth natural leather of adult beef that has been chromed and a cushion material composed of soft closed-cell foam made of polyurethane. A good and similar feel when touching a cushioning composite molded product consisting of a hard base made of a hard resin.

Poor: A feeling different from the above good feeling. Crane example 1 Comparative example 1 Experiment o.1-1 1-2 1-3 1-4 1 1 1 Hard resin PP GPP PP GPP Same as left material Rubber-like elastic body SB 1 Same as left SB 2 SB 1 Same as left ) BA 1 Same as left Same as left BA2 BA1

(Addition amount, warhead 90) 4 Same as left Same as left Same as left Same as left Elastic body thickness (concession) 3 Same as left Same as left Same as left Same as left Synthetic elastic fiber Full Same as left Same as left Same as left Short shot

Case Melted elastic body (.C) 205 Same as left Same as left Same as left Same as left-

30 Same left Same left Same left Same left Same left Opening time (seconds) 17 Same left Same left 20 Same left Same as left Same as left Same as left Same as left Same as left

a

an appearance good same left same left same same bad bad thing remarkable rough surface

Feeling Good Same Same as left Good Good Bad

Soft somewhat hard soft hard

Table 2 Example 2 Comparative Example 2 Experiment No. 2-1 2— 2 2- 3 2- 4 2-1 Hard resin PP Same as left Same as left GPP Same as left Material Rubbery elastic body SB 1 Same as left Same as left Same as left Material Blowing agent (Type ) BA 1 Same as left Same as left Same as left

1 2 4 Same as left Same as left Same as left Mold thickness of elastic body () 3 Same as left Same as left Same as left Same as left Full Elasticity Full Same as left Same as left Same as left Same shape

Article

Case Melted elastic body (.c) 205 Same as left Same as left Same as left Same as left Mold ΓΟ 30 Same as left Same as left 90 30 Mold opening start time (seconds) 1 7 Same as left Same as left 30 Same as left C ', retreat type Core release type Same as left Same as left Same as left Same as left Good Same as left Same as left Same as left No foaming

Shape

□

Appearance Good Same as left Same as left Same as left Bad object Matte

Feeling Good Good Same as on the left Same as on the left Bad Hard, soft Hard

Table 3 Difficult example 3

Experiment No. 3-1 3-2 3-3 3-4 Hard resin PP Same as left Same as left Same as left Material Rubbery elastic body SB 1 Same as left Same as left SB 3 Quantity mi (type) BA1 BA2 Same as left Same as left

"(Addition amount, weaver%) 2 Same as left Same as left Same as left Elastic body thickness Omi) 3 Same as left 2 Same as left Full Same as left Same as left Same as left

Article

Case Melt elastic CO 230 Same as left Same as left Same as left 麵 CO 25 Same as left Same as left Same as left Mold opening start time (sec) 1 Same as left Same as left Same as left Mold opening time (sec) 2 Same as left Same as left Same as left Molding distance (ran) 2 Same as left Same as Same as left Retreat type Core closed type Same as left Same as left Same as left Foaming form Same as left Same as left Very good

Shape

□ α Appearance m Same as left Same as left Very good

Good feel Same as left Same as left Very good

Software Industrial applicability>

The present invention is as described above, and has the following effects.

That is, in the first embodiment relating to the method for producing a composite molded article according to the present invention, the molding of the surface material, the molding of the cushion material, and the integration of the cushion material and the hard base material are performed in one. It is possible to reduce the labor and production cost in the manufacture of cushioning composite molded products, and in the second aspect, In addition, since the hard base can be continuously molded with the same mold, it is possible to further reduce the labor and production cost more than in the first embodiment. .

In addition, the cushioning composite molded article obtained by this method gives an excellent appearance and a soft touch, and is therefore extremely useful as various interior materials.

Claims

The scope of the claims

1. Either mount a hard base material that has been molded in a desired shape in advance into a mold having a gap larger than the hard base material, or inject a hard resin into a mold having a desired shape to form a hard base material. After the material is formed, the inside of the mold is larger than the hard base material, it is expanded to have gaps, and then the foamable rubber-like elastic material is injected into the gaps on the hard base material. Then, a foamable rubbery elastic body layer covered with a surface material as a skin layer is integrally formed, and the inside of the mold is further expanded to foam the foamable rubbery elastic layer. Forming a cushion material covered with the surface material by the method described above.

2. A cushioning composite molded article produced by the method according to claim 1.

3. An automotive part comprising a cushioning composite molded article produced by the method according to claim 1.

4. The average molecular weight of the rubber-like elastic material based on the GPC method is more than 30,000 and not more than 70,000, and the A hardness based on JISK6301 is more than 50, not more than 100. A cushion-type composite molded article produced by the method according to claim 1, wherein the molded article is a saturated styrene-based rubber-like elastic body.

5. The rubber-like elastic body has an average molecular weight based on the GPC method of more than 30,000 and not more than 70,000, and an A hardness of more than 50, based on JISK 631, of 10 The connection between a saturated styrenic rubber-like elastic material of 0 or less and a polyrefin.ゥ The hardness of this component is based on JISK6301 ΑHardness is more than 50 and less than〗 00 At a shear rate of 1,000 / sec.

It is manufactured by the method according to claim 1, which is within a range of not less than 5, OOO popise and not more than 50, OOO poise at a shear rate of not less than poise and not more than 3,000 poise and 1 O Zsec. A cushioning composite molded product.