JPH10147658A - Composite sheet, molded material and hot stamping molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a composite sheet capable of giving a shaped product without generation of undulations on the surface of a skin material by sticking a foamed sheet having a specific range of apparent density on at least one face of a polyolefinic resin foamed material. SOLUTION: This composite sheet is obtained by sticking a foamed sheet having 0.33-0.91g/cc apparent density on at least one face of a polyolefinic resin (preferably a polypropylene resin) foamed material. Preferably, a resinous sheet comprising a thermoplastic olefin elastomer having <=700KPa flexural modulus is provided on the face to be stuck with the above foamed sheet and a skin material is stuck on the other face to obtain the objective composite sheet for hot stamping molding. By using this composite sheet, a shaped product capable of widely using as an air blowing panel of a temperature regulator, a bag, etc., can be expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite sheet or molded article made of a polyolefin resin foam and a method of hot stamping molding. Conditioner) air blow-out panels and bags (including cases),
Or, preferably, it is widely used for vehicle interior parts such as door panels, ceiling materials, instrument panels, and the like.

The present invention has been studied for the purpose of industrially supplying these molded products inexpensively by the hot stamping molding method (reducing defects: eliminating avatars) and improving the tactile sensation. It is about providing.

[0003]

2. Description of the Related Art Heretofore, this type of constituent material has been formed by laminating a woven fabric, a soft vinyl chloride sheet or the like as a skin material on the surface of, for example, a polypropylene resin foam. This constituent material is placed in a molding die, and a resin, mainly a polypropylene-based resin is melted to be an aggregate, and is placed on the foam side in a molten state, for example, by injection or extrusion.
After the supply, a pressure is applied to integrally mold the constituent material and the molten resin. Also, Japanese Patent Application Laid-Open No. Sho 62-18111
As disclosed in Japanese Patent Application Publication No. 3 (1999), it is also known to protect a foam by laminating a film on the surface of the foam to be laminated with the aggregate.

[0004]

However, the following problems are pointed out in the conventional constituent materials. That is, when the molten resin for aggregate is supplied to the foam side of the constituent material to obtain a molded product, the foam is partially unevenly melted or crushed due to the temperature and pressure of the molten resin to be uneven in thickness. Therefore, the recoverability of the foam after the molding process is different, and as a result, unevenness is observed on the surface of the molded product, and a product without commercial properties is obtained. In order to reduce the expansion ratio of the polyolefin-based resin foam, there is also a problem that only a molded product having a hard and inferior feel can be obtained. In addition, the method of laminating the films has a problem that it is difficult to reduce the weight and the moldability is inferior.

An object of the present invention is to provide a molded product having no irregularities on the surface of a skin material in order to solve such problems.

[0006]

The present invention basically employs the following means in order to solve such problems. That is, "at least one surface of the polyolefin resin foam has an apparent density of 0.33 to 0.91.
Composite sheet laminated with g / cc foam sheet. ".

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The composite sheet or molded article according to the present invention is preferably a composite sheet for hot stamping molding, in which a skin material is bonded to one surface of a polyolefin resin foam, and the other surface. Has a flexural modulus of 700
A composite sheet obtained by laminating a resin sheet made of a thermoplastic olefin-based elastomer having a pressure of not more than KPa on a surface to be subjected to hot stamping molding, or stamping molding in which such a composite sheet is integrally molded with a resin so as to be a molten aggregate as a constituent material. Body.

The polyolefin resin constituting the foam is preferably a polypropylene resin, which contains 1 to 30% by weight of a propylene homopolymer or an α-olefin such as ethylene or butene-1, and has a random, random block or block content. Polypropylene resins copolymerized in a shape are preferred. These resins may be further mixed with other resins within a range that does not adversely affect the foam. For example, low-density, medium-density or high-density polyethylene, a polyethylene-based copolymer obtained by copolymerizing an α-olefin, or a copolymer with ethylene-based vinyl acetate or acrylate ester may be mixed.

The foaming agent is a compound which is liquid or solid at room temperature and decomposes or vaporizes when heated to a temperature higher than the melting point of the polypropylene resin, and does not substantially hinder sheeting or crosslinking reaction. It is preferable that the decomposition temperature is 180 to 240 ° C. Examples of such a thermal decomposition foaming agent include azodicarbonamide, azodicarboxylic acid metal salt, dinitrosopentamethylenetetramine, and the like. These foaming agents are used in the range of 0.1 to 40% by weight based on the polypropylene resin, and the mixing amount can be arbitrarily changed depending on each kind and apparent density.

As a crosslinking method, a known radiation crosslinking method or a chemical crosslinking method using an organic peroxide can be applied. To promote this crosslinking, a multifunctional monomer,
For example, divinylbenzene, diallyl phthalate and the like can be added.

The mixing of the polypropylene resin with a foaming agent, a crosslinking accelerator and the like includes, for example, mixing with a Henschel mixer, Banbury mixer, mixing roll, or the like, or a mixing method using a kneading extruder. In particular, when the resin is in a powder form, powder mixing by a Henschel mixer is convenient. Powder mixing is usually carried out between room temperature and the softening temperature of the resin, and melt mixing is usually carried out in the range from the melting temperature of the resin to 195 ° C. When producing a continuous sheet-like foam, it may be formed into a sheet by extrusion at a temperature not higher than the decomposition temperature of the foaming agent.

The apparent density of the polypropylene resin foam used in the present invention is preferably 0.025 to 0.200 g /
cc. This is the apparent density of the foam = {10 cm × 10 cm × 10 cm weight} / {10 cm × 1
0 cm × 10 cm volume}. If the apparent density exceeds 0.200 g / cc, the flexibility and tactile sensation become poor, and if the apparent density is less than 0.025 g / cc, the material strength is weak and the bubbles are easily broken.

The gel fraction of the polypropylene resin foam used in the present invention is preferably at least 20%, more preferably 45 to 60%. If the gel fraction is less than 20%, the material strength is weak at the time of lamination with the foamed sheet, and it is not desirable because the bubbles are broken. On the other hand, if the gel fraction exceeds 70%, foaming cannot be performed sufficiently, and flexibility and tactile sensation become poor.

The gel fraction of the polypropylene resin foam is measured as follows.

First, the foam is cut into approximately 1 mm squares.
Approximately 1 g is collected, precisely weighed as a sample, and its weight is defined as A (g).

The sample is heated in a tetralin at a temperature of 130 ° C. for 3 hours, cooled, washed with acetone, washed with water to remove elution, and dried. The dried sample is precisely weighed and its weight is defined as B (g).

The gel fraction (%) is calculated by the following equation.

Gel fraction (%) = (B / A) × 100 The foamed sheet in the present invention is not particularly limited. However, considering the workability during hot stamping molding, the flexural modulus is 700 KPa. The following thermoplastic olefin-based elastomer resin is preferably used and is composed of butene-ethylene and ethylene-propylene, and has an apparent density of preferably 0.33 to 0.83 g / cc, and 0.5 to 0.67 g / cc. cc is more preferred. In addition, this is the same as the case of the foam, the apparent density of the foam sheet = {10 cm × 10 cm × 10 cm weight} / {10c
m × 10 cm × 10 cm volume}.

For bonding to the polyolefin resin foam, an extrusion method (EL method) or a heat bonding method is employed.
When laminating by the EL method, it is preferable to add a pyrolytic foaming agent to the thermoplastic olefin-based elastomer resin so that the apparent density is 0.33 g / cc or more and 0.91 g / cc or less. If it exceeds 0.91 g / cc, sufficient weight reduction cannot be achieved, while if it is less than 0.33 g / cc, heat resistance is reduced and avatars are caused. The flexural modulus of the foamed sheet is preferably 700 KPa or less, more preferably 150 to 400 KP.
a. If it exceeds 700 KPa, the end of the molded product obtained by the hot stamping molding method using the composite sheet (constituent material) of the present invention is processed. For example, when the composite sheet (constituent material) is spread on the back side, the flexural modulus is reduced. If it is too large, a problem of causing a snapping phenomenon occurs. Conversely, if it is too low, the melting point will be low, and it will not be able to withstand the heat during molding. Further, the thickness of the foamed sheet is not particularly limited, but if it is too thick, wrinkles will occur, and if it is too thin, there will be no protective effect and avatars will be formed on the molded product at resin temperature and pressure. ~ 2 mm is preferred,
0.2 to 0.6 mm is more preferable.

The skin material of the present invention is not particularly limited, but a cloth material using natural or artificial fibers, a sheet made of polyvinyl chloride resin, a thermoplastic elastomer sheet, leather, polyvinyl chloride resin A known material such as a mixed sheet of ABS and an ABS resin can be used.

The substrate is not particularly limited, but a thermoplastic resin is suitable for application to stamping molding, and a polyolefin resin is preferable. Above all, preferably, in consideration of heat resistance and mechanical strength, polypropylene resin, or propylene and α-olefin are random, random-block, polypropylene resin copolymerized in block form, polyethylene resin or ethylene and α-olefin , A copolymer resin with vinyl acetate or acrylic acid ester, a resin in which these are arbitrarily mixed, and the like can be applied.
Further, an inorganic compound such as talc, silicic acid, or calcium carbonate may be mixed with these resins as a filler as long as the properties of the base resin are not impaired. In addition, known heat stabilizers, antioxidants, nucleating agents, coloring agents, and the like may be added to the base resin as necessary. Further, a non-olefin resin such as an ABS resin, a polystyrene resin, and a petroleum resin may be added as long as the moldability is not impaired. A so-called hot stamping molding method that can set the molding pressure smaller than that of injection molding is preferable.

FIGS. 1 to 3 are explanatory views showing an example of a hot stamping molding method.

As shown in FIG. 1, a foam sheet 1 and a composite material in which a skin material 2 is bonded to an olefin resin foam 3 on the opposite surface are arranged at predetermined positions of a pair of upper and lower molds 4 and 5.
An appropriate amount of molten thermoplastic resin 6 for a base material is supplied to the molding surface on the foam sheet 1 side (the molding surface of the lower mold 5 in this example). Then, as shown in FIG. 2, the base material 6 was integrally formed on the foam sheet 1 side of the composite material 3 by press-molding under predetermined temperature conditions with the molds 4 and 5 as shown in FIG. The vehicle interior molded product 7 is obtained.

FIGS. 4 to 6 are explanatory views showing other examples of the hot stamping molding method. In this example, as shown in FIG. 4, the preformed composite material 3 is arranged at a predetermined position of the molding die 5 so that the foam sheet 1 is on the upper side,
A molten thermoplastic resin 6 for a base material is supplied onto the foam 1. Then, as shown in FIG. 5, by performing pressure molding, a molded product is obtained as shown in FIG.

[0025]

【Example】

Examples 1 to 9 and Comparative Examples 1 to 3 First, hexene having an MI6 density of 0.915 g / cm ³ was used as a comonomer in 80% of a polypropylene resin in which ethylene was randomly copolymerized at 3.0% by weight as a foam. 5 parts by weight of a thermal decomposition type blowing agent azodicarbonamide was added to 100 parts by weight of a mixture with 20% of a certain linear polyethylene resin,
7.5 parts by weight, or 10 parts by weight, 4 parts by weight of dienyl benzene as a cross-linking aid, 0.3 part by weight of Irganox 1010 as a phenolic stabilizer and distearyl 3,3-thiodipropionic acid as a sulfuric stabilizer After uniformly mixing 0.2 parts by weight of the ester with a Henschel mixer, (1) a sheet was formed with an extruder so that the thickness of the foam obtained by the T-die method was 3 mm.

(2) After irradiating the obtained sheet with an electron beam so that the gel fraction of the foam becomes 53 to 55%,
Foamed on a salt bath heated to 235 ° C.

(3) One side of the obtained foam has a thickness of 0.6
mm soft polyvinyl chloride sheet was bonded using a polyester adhesive.

(4) Further, on the other side, as a foam sheet,
A non-crosslinkable polyolefin-based thermoplastic elastomer resin having a flexural modulus of 250 K and a copolymer of ethylene and 29% MI1.5 propylene, and dinitrosopentamethylenetetramine and azodicarbonamide in a 1: 1 ratio as pyrolytic blowing agents. A foamable polyolefin-based thermoplastic elastomer mixture in which 0.45 to 1.5 parts by weight of the mixed foaming agent is mixed with respect to 100 parts by weight of the resin has a sheet thickness of 0.3.
mm and were laminated by an extruder T-die method. It foamed by the heat of the extrusion operation.

(5) With respect to the resulting (soft polyvinyl chloride sheet) / (polyolefin resin foam) / (thermoplastic elastomer sheet) constituent material, a MI40 or MI1.5 polypropylene resin is used as a base resin. Placed on the surface of the thermoplastic elastomer sheet of the component, 35
Hot stamping molding was performed using a box-shaped mold of 0 × 350 × 50 mm. At this time, the resin temperature was 200 ° C. or 240 ° C., the resin was integrally molded at a molding pressure of 50 kg / cm ² , and surface irregularities (avatar (orange peel)) were observed. The following results were obtained.

[0030]

[Table 1] Note) ◎: No irregularities are seen at all ○: Feels as if slight irregularities are seen △: Irregularities are seen and no commercial value ×: Irregularities are seen over the entire surface

[0031]

The composite sheet for hot stamping of the present invention has a remarkable effect that the surface irregularity does not occur even when the temperature of the base resin is high, and the range of molding conditions is wide.

[Brief description of the drawings]

FIG. 1 shows a molding method (before molding) in which a base material is placed below.

FIG. 2 shows a molding method (under molding) in which a base material is placed below.

FIG. 3 shows a molding method (after molding) in which a substrate is placed below.

FIG. 4 shows a molding method (before molding) in which a base material is arranged on the upper side.

FIG. 5 shows a molding method (during molding) in which a base material is arranged on the upper side.

FIG. 6 shows a molding method (after molding) in which a base material is arranged on the upper side.

[Explanation of symbols]

 1: foam sheet 2: skin material 3: olefin resin foam 4: upper mold 5: lower mold 6: thermoplastic resin

Claims (12)

[Claims] 1. A composite sheet in which a foamed sheet having an apparent density of 0.33 to 0.91 g / cc is attached to at least one surface of a polyolefin resin foam. 2. The composite sheet according to claim 1, wherein a skin material is bonded to the other surface of the foam sheet. 3. A molded product, characterized in that a thermoplastic resin base material is provided on the surface of the composite sheet according to claim 1, to which the foamed sheet is bonded. 4. The composite sheet according to claim 2, wherein the skin material is made of a polyvinyl chloride resin sheet to which a drawn pattern is added. 5. The composite sheet according to claim 2, wherein the skin material comprises a thermoplastic elastomer sheet to which a drawn pattern is added. 6. The polyolefin resin foam has an apparent density of 0.025 to 0.200 g / cc and a gel fraction of 20 to 7
The composite sheet according to claim 1, wherein the content is 0%. 7. The composite sheet according to claim 1, wherein the foamed sheet is a non-crosslinked type thermoplastic olefin elastomer resin. 8. The composite sheet according to claim 7, wherein the foamed sheet is a crosslinked thermoplastic olefin elastomer resin. 9. The composite sheet according to claim 7, wherein the thermoplastic olefin elastomer constituting the foamed sheet has a flexural modulus of 700 MPa or less. 10. The foam sheet has an apparent density of 0.83 to 0.83.
2. The composite sheet according to claim 1, wherein the weight is 0.33 g / cc. 11. The molded article according to claim 3, wherein the thermoplastic resin base material is a polypropylene resin. 12. A hot stamping molding method using the composite sheet according to claim 1.