JPH0939015A - Production of multilayered product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply produce a recyclable multilayered product good in appearance in low cost. SOLUTION: A surface layer material is a thermoplastic elastomer of which the melt flow rate at 230 deg.C under load of 2.16kg is 5-200g/10min and a base material is a thermoplastic resin and partially supplied into molds 1, 2 in a molten state and, thereafter, the surface layer material 5 and the base material 4 are co-extruded in a molten state in a multilayered state so that the base material 4 is brought into contact with the base material 4 supplied into the molds 1, 2 to be laminated thereto and the whole is subjected to compression molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multi-layered article, and more particularly to an efficient method for producing a compression-molded article having a very good appearance.

[0002]

2. Description of the Related Art Conventionally, when a polypropylene base material is used for a laminated molded article of a surface layer material and a resin base material in an automobile interior, the base material is first molded by injection molding and then a surface layer material such as vinyl chloride leather, Alternatively, it is manufactured by a method in which a laminate of a surface layer material and a plastic foam is attached to the base material with an adhesive at the same time as vacuum forming. However, in this method, an adhesive must be used, which causes a problem of deteriorating the working environment and complicates the working process. In order to improve these points, in recent years, a method of placing a surface layer material or a laminated material of the surface layer material and a plastic foam in a mold, melt-feeding a resin as a base material, and then compression-molding the resin has been implemented. In this method, although the problem of the working environment is improved, the surface material is damaged by heat and pressure during molding, resulting in appearance problems such as grain flow, unevenness of the surface material, and pockmarks. In addition to the complexity of post-processing such as the step of trimming the surplus part of the surface layer material used and folding back the surface layer material after molding to the back side of the base material, a large amount of trimming scraps are generated, resulting in cost reduction. It is disadvantageous and also causes recycling problems. On the other hand, as a molding method for laminating two kinds of different resins, there is a so-called two-color molding method in which two sets of molds are molded by injection molding. However, in this case, since two sets of molds are used for one mold clamping device, the device including the mold rotating mechanism and the like becomes complicated and the cost increases. In addition, at present, it is not possible to deal with large molded products. Further, Japanese Patent Application Laid-Open No. 4-4147 discloses a laminated molded body composed of a specific polypropylene-based composite resin and a specific thermoplastic elastomer, and a method for producing the laminated molded body. Sometimes you can't get it. JP-A-3-2651
Japanese Patent Publication 7 discloses a method and an apparatus for producing a multilayer product, but hardly describes the resin used. When molding is carried out by these methods, appearance defects such as charge marks on the design surface of the molded product, exposure of the base material resin at the end of the molded product, and mixing of the surface layer material and the base material in the complicated part of the shape occur, A molded product with a good appearance cannot be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and has a low cost and has a good appearance and is a recyclable multilayer which has not been possible by the conventional compression molding method. The object is to provide an efficient compression molding method for a product.

[0004]

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, the surface layer material has a melt flow rate of 5 to 200 g / 10 at a temperature of 230 ° C. and a load of 2.16 kg. A thermoplastic elastomer, the base material is a thermoplastic resin, and after the base material is partially supplied in a molten state into a mold, the surface layer material and the base material are melted to form a multilayer sheet. It has been found that this can be solved by a method for producing a multilayer product in which a base material supplied by extrusion into the mold and the coextrusion base material are laminated so as to be in contact with each other, and then the mold is closed and pressure-cooled.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. (A) Surface Layer Material The surface layer material of the present invention is composed of a thermoplastic elastomer having a melt flow rate of 5 to 200 g / 10 minutes at a temperature of 230 ° C. and a load of 2.16 kg, and flows with heating with the thermoplastic elastomer. A material that can be molded and processed like ordinary thermoplastics and exhibits rubber elasticity at room temperature. Among them, hydrogenated products of propylene-based elastomer (TPO) which is an olefin-based elastomer and styrene-butadiene copolymer elastomer having a styrene content of 30% by weight or less particularly satisfy the product appearance and physical properties as a surface layer material, and have an inner layer. It is more preferable because it has good melt adhesion with the material. In the case of a hydrogenated product of a styrene-butadiene copolymer elastomer having a styrene portion of more than 30% by weight, rubber elasticity is small and therefore the surface hardness of the molded product becomes high, and a cushion feeling cannot be obtained. At the same time, the adhesiveness to the thermoplastic resin used, especially to the olefin resin, is lost on the substrate. Further, the thermoplastic elastomer of the present invention, if necessary, generally used stabilizers, flame retardants, processability improvers, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, colorants, Needless to say, additives such as pigments and various fillers may be added.
The melt flow rate of the thermoplastic elastomer of the surface layer material at a temperature of 230 ° C. and a load of 2.16 kg (hereinafter, MF
R is abbreviated as R), preferably 5 to 200 g / 10 minutes, more preferably 10 to 150 g / 10 minutes. When it is less than 5 g / 10 minutes, the fluidity as a surface layer material becomes insufficient, which makes it difficult to control the thickness and causes an appearance defect due to flow marks. If it exceeds 200 g / 10 minutes, molding problems such as adhesion to the die lip will occur, and the physical properties required for the surface layer material such as heat resistance and scratch resistance will be poor. The crystallization temperature of the thermoplastic elastomer is
It is preferable that the temperature lowering rate is 80 to 100 ° C. at a temperature of 20 ° C./min and the isothermal crystallization start time at 103 ° C. is 5 to 60 seconds. The crystallization temperature of the thermoplastic elastomer can be measured by a differential calorimeter at a temperature decreasing rate of 20 ° C / min. Further, the isothermal crystallization start time at 103 ° C. is when the temperature is lowered from 230 ° C. to 80 ° C./min by the same measuring device and the temperature is kept at the time of reaching 103 ° C.,
The time from when the temperature reached 103 ° C. to when the crystallization started was defined. If the crystallization temperature exceeds 100 ° C, the flow will stop at an early stage during molding, and the substrate cannot be covered evenly. If the temperature is less than 80 ° C, the cooling cycle cannot be quickly performed, and mechanical damage such as scratches may occur when the molded product is taken out. Further, if the isothermal crystallization start time at 103 ° C. is less than 5 seconds, the crystallization progresses sensitively to the cooling of the molding depending on the touch of the mold, so that the unevenness of gloss on the surface of the molded product due to the difference in the mold touch time. Or transfer failure occurs. If it exceeds 60 seconds, the softening state continues forever and the cooling cycle becomes long, which is not practical.

(B) Substrate The substrate of the present invention is made of a thermoplastic resin, of which an olefin resin is preferable, and a propylene resin is more preferable because it has good moldability and product properties. As the propylene-based resin, propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer and mixtures thereof, and other resins containing the propylene-based resin, such as polyethylene, ethylene-α-olefin A mixture with a copolymer elastomer, a styrene-butadiene copolymer elastomer, a derivative thereof and the like is also included. The thermoplastic resin of the present invention may be used alone or in combination of two or more, and a mixture of fillers such as talc, glass fiber and wood powder may also be used as the thermoplastic resin. If necessary, commonly used stabilizers, flame retardants, processability improvers, lubricants,
It goes without saying that additives such as antistatic agents, antioxidants, ultraviolet absorbers, colorants and pigments may be added. Base material thermoplastic resin temperature 230 ° C, load 2.16
The MFR in kg is preferably 3 to 40 g / 10 minutes, more preferably 5 to 30 g / 10 minutes. If it is less than 3 g / 10 minutes, the fluidity as the inner layer material is insufficient and the molded product becomes a short shot. If it exceeds 40 g / 10 minutes, the mechanical properties, especially the impact resistance, are poor. However, this MF
The value of R is only a guide, and the important thing is 500
At a shear rate of sec ^-1 , the viscosity at 210 ° C is 7 ×
It is preferably 10 ² to 4 × 10 ³ poise, more preferably 8 × 10 ^{2 to} 3 × 10 ³ poise, and further preferably 1
If a product of × 10 ^{3 to} 2.5 × 10 ³ is used, a good molded product can be obtained. The viscosity of thermoplastic resin is JIS-K71
The relationship between shear rate, temperature and viscosity can be measured by a Capillograph (manufactured by Toyo Seiki) in accordance with the flow characteristic test method of 99 thermoplastics using a capillary rheometer. The viscosity in this range is the optimum viscosity for charging the coextruded sheet, and when it is less than 7 × 10 ² poise, an overlap occurs when the sheets are supplied, and as a result, the surface layer elastomer and the base resin are not compressed during compression molding. Mixing occurs and it becomes a mottled pattern. On the other hand, when a resin having a porosity of more than 4 × 10 ³ poise is used, the drawdown of the resin at the time of melting is small, and the sheet cannot be supplied in a desired sheet shape according to the shape of the product. In this case, since the distance required for fluidization during pressurization becomes long, the surface layer material is damaged at the end of the molded product. Both of them have a poor appearance.

(C) Multilayer product The multilayer product in the present invention comprises a surface layer material and a base material, and the surface layer material is a material of one layer or two or more layers located on one surface side of the multilayer product and covering the base material. The material is one or more layers of material covered with the surface material. When the surface layer material or the base material is a single layer, the thermoplastic elastomer which is the surface layer material and / or the thermoplastic resin which is the base material is foamed to give a cushioning property to further enhance the appearance and enhance the design. , Can be made lighter. When the surface layer material or the base material has two or more layers, it is also possible to foam one layer of the thermoplastic elastomer which is the surface layer material on the side in contact with the base material or the thermoplastic resin which is the base material on the side in contact with the surface layer material. The foam can be obtained in the compression molding process from the melting process by the extruder to the process of solidifying after mold clamping. Specifically, the thermoplastic elastomer and / or thermoplastic resin of the layer to be foamed is kneaded with a foaming agent in advance to form pellets having a foaming ability, and the pellets are extruded from the extruder at a temperature suitable for the foaming agent. It can be obtained by melt-supplying, foaming, post-mold clamping, and appropriately controlling the clearance of the mold, the timing of opening and closing, the mold clamping force, and the like. When the adhesive force between the surface layer material and the base material is insufficient, one of the surface layer material or the base material is formed into two layers, and a thermoplastic elastomer or thermoplastic resin having high adhesiveness is interposed to form three layers as a whole. It can be used for laminating various resins. In the multilayer product of the present invention, the relationship between the thickness of the surface layer material and the base material is preferably that the thickness of the base material is larger than the thickness of the surface layer material because the mechanical properties of the product are improved, but it is appropriately selected according to other purposes. Of course you can. When the thickness of the base material is larger than the thickness of the surface layer material, the MFR of the surface layer material is preferably larger than the MFR of the base material. When the MFR of the surface layer material is equal to or smaller than the MFR of the base material, the surface layer material cannot cover the base material evenly, and the base material is exposed on the surface of the product to impair the appearance. It is possible to give various grain patterns to the surface material of the multilayer product of the present invention, and by using the surface material of the present invention, uniform contact with the molding die is achieved, and the grain pattern is transferred cleanly. A molded product with a good appearance can be obtained. Further, it is possible to decorate the surface by using it in combination with other molding methods, transfer a pattern, and insert molding other films, sheets, skin materials, etc., and further improve the designability.

(D) Molding Method In the multilayer product of the present invention, as a first step, the base material is first partially fed in a molten state into the mold attached to the compression molding machine, and then the shape of the final molded product is obtained. Partially solidify and shape so as not to satisfy. Specifically, it is performed on a portion of the final molded product that is thick as viewed from the surface layer material surface, for example, a portion such as a boss or a rib and its peripheral portion. In this case, the space of the rest of the shape is 10 mm in the thickness direction from the surface of the final molded product.
The following is preferable because the effect of preventing sink marks is large. Next, in the second step, the surface layer material and the base material are melted to form a multilayer sheet, preferably the surface layer material and the base material have a thickness of 1
Co-extrusion is performed so that the thickness becomes 0 mm or less, and the base material supplied into the mold and the co-extrusion base material are laminated so that they come into contact with each other, and then the mold is closed to perform compression molding into the shape of the final molded product.
After that, a mold is obtained by opening the mold. INDUSTRIAL APPLICABILITY The method of the present invention is suitable for molding a multi-layered product having a portion whose maximum thickness in the direction perpendicular to the surface material surface of the multi-layered product exceeds 10 mm, preferably 20 mm. Examples of the portion include the bosses and ribs described above. As in the present invention, as a first step, by filling and shaping a thick three-dimensional shape portion such as a boss or a rib with a resin in advance, even in a shape product having a locally thick portion, a sink mark or a resin is formed. The loss of
It is possible to obtain a molded product having a good appearance. As a method of supplying the resin as described above, the extruder in the first stage and the extruder in the second stage may be separate or shared. In the former case, the supply of the molten resin in the first stage is not limited to the sheet shape from the T-die, but may be a round bar or a pipe shape. Alternatively, an injection method may be used in which a nozzle is used to pass through a mold runner and a gate. In the second step, a method of co-extruding the surface layer material and the base material in a molten state from the multilayer T die using a plurality of extruders is preferable. Various devices can be used as the compression molding machine used in the present invention, and the pressure at the time of compression can be appropriately set depending on the molded product.

Since the multilayer article of the present invention comprises a specific surface layer material and a base material, the surface layer material can uniformly cover the base material during molding of the multilayer article, and no scraps are generated. This is because the viscosity of the thermoplastic resin of the base material is appropriately controlled and the flat resin can be supplied onto the mold. In addition, by molding in two steps, even a locally thick-walled product can be obtained, and a product with good appearance without defects is obtained. Further, since the solidifying speed of the surface layer material is moderately slow, the surface layer material can uniformly contact with the surface of the mold, and the shape of the mold is transferred as it is, resulting in a multilayer product having a good appearance. Further, by using an olefin-based elastomer or a hydrogenated product of a styrene-butadiene copolymer elastomer having a styrene content of 30% by weight or less as the surface layer material and selecting an olefin-based resin as the base material, recycling is possible.

[0010]

【Example】

(Example 1) A propylene-based elastomer (hereinafter abbreviated as TPO) containing 63% by weight of an ethylene-propylene copolymer having an MFR of 10 g / 10 minutes and a propylene content of 70% by weight was used as a surface layer material. MFR as material
Is 20 g / 10 minutes and the propylene content is 50% by weight.
A blend containing 20% by weight of talc to 80% by weight of a propylene-ethylene block copolymer consisting of 20% by weight of the ethylene-propylene copolymer and 80% by weight of propylene was used. First, as the first step, the base material is a two-layer
1 in one extruder of hot flow molding machine with die
It was melted at 85 ° C., and it was extruded as a single layer from a T die and supplied onto a lower mold. Here, the upper mold and the lower mold were closed, and after the mold was clamped for 5 seconds, the molded product was left in the lower mold and the mold was opened. The molded product at this time is 30 in the direction perpendicular to the surface layer surface.
It had a boss with a thickness of mm. Next, the surface layer material and the base material were coextruded with a hot flow molding machine having a two-layer T die at a temperature of 185 ° C. to supply the surface layer material and the base material onto the intermediate shape base material. The upper mold and the lower mold were compressed and clamped again, and after cooling, the mold was opened and the molded product was taken out. The results are shown in Table 1. The obtained molded product has a shape as shown in FIG.
The substrate was a multilayer product having a thickness of 2.5 mm, the grain pattern of the upper mold was clearly transferred, and molding was possible without generation of the surface layer material and the end material of the substrate. The molding conditions in this example were set as follows. Upper mold temperature:
60 ° C, lower mold temperature: 40 ° C, pressurizing pressure: 50 kg /
cm ² , cooling time: 25 seconds.

(Example 2) MFR as a surface layer material is 40 g
TPO containing 70% by weight of an ethylene-propylene copolymer having a propylene content of 70% by weight, a MFR of 10 g / 10 min as a base material, 90% by weight of a propylene homopolymer and propylene. The same procedure as in Example 1 was performed except that a blend containing 15% by weight of talc was used for 85% by weight of a mixture of 10% by weight of ethylene-propylene copolymer having a content of 40% by weight, and extruding at 200 ° C. It was The cooling time was 40 seconds. The results are shown in Table 1.

(Example 3) MFR as a surface layer material is 80 g
Example 10 was repeated except that TPO containing 55% by weight of an ethylene-propylene copolymer having a propylene content of 70% by weight was used. Cooling time is 30
Seconds. The results are shown in Table 1.

(Embodiment 4) The surface layer material has an MFR of 160.
TPO containing 67% by weight of ethylene-propylene copolymer having a propylene content of 70% by weight.
Using a propylene-ethylene block copolymer consisting of 15% by weight of an ethylene-propylene copolymer having an MFR of 8 g / 10 minutes and a propylene content of 50% by weight and 85% by weight of propylene as a base material. The same procedure as in Example 1 was carried out except that extrusion was carried out at a temperature of ° C. The cooling time was 35 seconds. The results are shown in Table 1.

(Example 5) MFR as a surface layer material is 20 g
/ 10 minutes, using a hydrogenated product of a styrene-butadiene copolymer elastomer having a styrene content of 18% by weight, a base material having an MFR of 5 g / 10 minutes and an ethylene content of 3% by weight. The same procedure as in Example 1 was carried out except that an ethylene random copolymer was used and extruded at 230 ° C. The cooling time was 45 seconds. The results are shown in Table 1.

(Example 6) MFR as a surface layer material is 30 g
Ethylene having a styrene content of 25% by weight and a styrene-butadiene copolymer elastomer hydrogenated product with a MFR of 25 g / 10 minutes and a propylene content of 50% by weight. Example 1 was repeated except that a propylene-ethylene block copolymer consisting of 22% by weight of propylene copolymer and 78% by weight of propylene was used and extruded at 185 ° C. The cooling time was 45 seconds. The results are shown in Table 1.

Example 7 Example 1 was repeated except that the same TPO as in Example 4 was used as the surface layer material and a propylene homopolymer having an MFR of 30 g / 10 min was used as the base material and extruded at 210 ° C. I went the same way. Cooling time is 35
Seconds. The results are shown in Table 1.

(Embodiment 8) As the first step, the same procedure as in Embodiment 1 was carried out except that the base material was melted at 200 ° C. with an extruder having another round bar-shaped die, extruded, and fed onto the lower mold. It was The cooling time was 25 seconds. The results are shown in Table 1.

(Comparative Example 1) MFR as a surface layer material is 3 g /
Examples except that TPO containing 10% and 72% by weight of an ethylene-propylene copolymer having a propylene content of 70% by weight was used, and a propylene homopolymer having an MFR of 30 g / 10 minutes was used as a base material. The same procedure as 1 was performed.
The cooling time was 75 seconds. The results are shown in Table 2.

(Comparative Example 2) As a base material, MFR was 80 g /
10 minutes, 87% by weight of a mixture of 85% by weight of a propylene homopolymer and 15% by weight of an ethylene-propylene copolymer having a propylene content of 40% by weight, and 1% of talc.
Example 1 was repeated except that a blend containing 3% by weight was used. The results are shown in Table 2.

(Comparative Example 3) The surface layer material has an MFR of 220.
TPO containing 45% by weight of ethylene-propylene copolymer having a propylene content of 70% by weight.
Using a propylene-ethylene block copolymer consisting of 12% by weight of an ethylene-propylene copolymer having a propylene content of 50% by weight and 88% by weight of propylene as a base material. The same procedure as in Example 1 was carried out except that extrusion was carried out at a temperature of ° C. The cooling time was 25 seconds. The results are shown in Table 2.

(Comparative Example 4) The surface layer material and the base material were supplied to the lower mold from a hot flow molding machine having a two-layer T-die, and a molded product in two steps was not prepared, and the same manner as in Example 1 was performed. I went the same way. The cooling time was 30 seconds. The results are shown in Table 2.

(Comparative Example 5) MFR as a surface layer material is 10 g
Example 10 was repeated except that a hydrogenated product of a styrene-butadiene copolymer elastomer having a styrene content of 40% by weight was used. Cooling time is 85
Seconds. The results are shown in Table 2.

(Comparative Example 6) MFR as a base material is 1 g / 1
Example 1 except that a propylene-ethylene block copolymer consisting of 10% by weight of an ethylene-propylene copolymer having a propylene content of 50% by weight and 90% by weight of propylene was used and was extruded at 260 ° C. I went the same way. The cooling time was 25 seconds. The results are shown in Table 2.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

According to the present invention, the following effects can be exhibited. (1) By direct transfer from the mold, it is possible to obtain a multi-layered product having a clear textured pattern and a very good appearance, and even a product having a partially thick portion such as a boss or a rib does not have a sink mark or a defect. A molded product is obtained. (2) A multi-layer product having good adhesion between the surface layer material and the substrate can be obtained. (3) Compared with the conventional skin attachment molding, there is no end material loss of the surface layer material, and in addition, the winding treatment of the surface layer material is not necessary, and labor saving and cost reduction can be achieved. (4) When the surface layer material and the base material are olefin-based, they can be recycled. (5) The conventional compression molding machine can be used, and the burden on the apparatus cost is light. In addition, the equipment and mold are simpler than those of multicolor injection molding. (6) The multilayer product of the present invention can be used in various fields. Among them, it is suitable as a material in the automobile interior field, and typical applications include door trims, pillars, console boxes, seat back panels, and the like.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a method for manufacturing a multilayer product according to the present invention.

FIG. 2 is an elevational view showing an example of a state in which a surface layer material and a base material are compressed by upper and lower molds in molding a multilayer product according to the present invention.

FIG. 3 is a plan view of a door trim of an automobile interior material which is an example of the multilayer product of the present invention.

[Explanation of symbols]

 1 Upper mold 2 Lower mold 3 Hot flow molding machine die 4 Base material 5 Surface layer material 6 Boss

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display B29L 9:00

Claims (5)

[Claims] 1. The surface layer material has a temperature of 230 ° C. and a load of 2.16.
Melt flow rate in kg is 5 to 200 g / 10
A thermoplastic elastomer, the base material is a thermoplastic resin, and after the base material is partially supplied in a molten state into a mold, the surface layer material and the base material are melted to form a multilayer sheet. A method for producing a multi-layer product, which comprises extruding and laminating so that the base material supplied into the mold and the co-extruded base material are in contact with each other, then closing the mold and pressurizing and cooling. 2. The surface layer material and the base material are coextruded so that the thickness of the coextruded surface layer material and the base material is 10 mm or less, and the maximum thickness in the direction perpendicular to the surface layer material surface of the multilayer product is 10 mm. The method for manufacturing a multilayer product according to claim 1, wherein the method has a portion that exceeds the limit. 3. The thermoplastic resin has a viscosity at 210 ° C. of 7 × 10 ² to 4 × 1 at a shear rate of 500 sec ^−1.
It is 0 ³ poise, The manufacturing method of the multilayer article as described in any one of Claims 1-2. 4. The thermoplastic elastomer has a cooling rate of 20.
The multilayer product according to any one of claims 1 to 3, wherein the crystallization temperature at ° C / min is 80 to 100 ° C and the isothermal crystallization start time at 103 ° C is 5 to 60 seconds. Manufacturing method. 5. The thermoplastic elastomer is a hydrogenated product of an olefin elastomer and / or a styrene-butadiene copolymer elastomer having a styrene content of 30% by weight or less, and the thermoplastic resin is an olefin resin. The method for producing a multilayer product according to any one of claims 1 to 4.