JPH07256765A - Manufacture of foam molded body which is coated with skin material - Google Patents

Abstract

PURPOSE:To prevent a cell of a part of a foam coming into contact with a synthetic resin film containing a lubricant from being roughened. CONSTITUTION:After a synthetic resin film surface of a skin material possessing a thermoplastic resin film 2 containing a lubricant on at least one surface is corona-discharge-processed beforehand, it is hot-molded within a molding tool by taking the synthetic resin film surface as the inside and then in the same mold, an unfoamed stock solution of a foaming synthetic resin is cast into the molded skin material and foamed. Hereby, hindering of a function of a foam stabilizer stabilizing foaming of a foaming material is eliminated and a uniform foam 13 free from roughening of a cell is formed on the inside of the skin material.

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 foamed molded product, such as an automobile seat or a bedding mat, in which a foamed material is covered with a skin material.

[0002]

2. Description of the Related Art In order to cover the surface of a foamed molded product such as a synthetic resin used as a cushioning material for seats or bedding, conventionally, a foamed product having a predetermined shape is molded in a molding die. Separately, it was covered with a cut and sewn skin material, or after vacuum forming a skin material such as cloth into a predetermined shape, the foam material was foamed in the same mold.

However, according to the former method, the manufacturing of the skin material is complicated, and when the shape is complicated, the manufacturing is difficult and impractical. In addition, the latter method can produce a complicated shape, but defects are likely to occur depending on the manufacturing conditions, and once a defect occurs, it cannot be regenerated, and the material, including expensive upholstery material, is wasted. There is a drawback that

As described above, in the latter method, how to eliminate defects is the key to stabilizing the manufacturing cost. In the latter method, when a breathable material such as cloth is used as the skin material, the skin material in the molding die is vacuum-formed into a predetermined shape, and when the foam material is foamed in the same forming die. In order to prevent the foamed material from being more stained than the skin material, a sheet is formed by laminating a synthetic resin film on a skin material such as cloth or a laminated synthetic resin on the skin material.

The synthetic resin film is usually made of polyurethane as the foaming material to be foamed in the forming mold. Therefore, a polyurethane film is generally used in consideration of adhesiveness.

In the case of a film such as a polyurethane film which is flexible and rich in elasticity and has a weak elasticity, its slipperiness is particularly advantageous for workability such as winding and rewinding during film production or secondary processing. It has a great influence. Therefore, a method has been used in which a lubricant such as a wax component that improves the slipperiness of the film is mixed into the material during film production.

[0007]

However, the lubricant in the film hinders the function of the foam-forming agent that stabilizes the foaming of the foaming material that foams in the forming mold, and the bubbles are broken near the film surface. It induces abnormal foaming called so-called cell roughening, in which bubbles do not form uniform foam.

This tendency becomes more remarkable as the proportion of the lubricant contained in the film is higher, and if the proportion of the lubricant is the same, the higher the heat applied to the film, and the longer the time from the production is. So remarkable. It is considered that this is because the lubricant exudes on the surface with heating and aging.

The present invention can be applied to a film containing a lubricant,
It is an object of the present invention to provide a method for producing a foam molded article covered with a skin material capable of preventing cell foaming of a foam material.

[0010]

In order to achieve the above-mentioned object, the present invention (Claim 1) is directed to corona discharge on the surface of the synthetic resin film of a skin material having a synthetic resin film containing a lubricant on at least one surface thereof. After the treatment, the synthetic resin film surface is used as the inner surface and is molded along the inner surface of the mold in the molding die, and then, in the same mold, the unfoamed stock solution of the foamed synthetic resin is injected into the molded skin material. It is characterized by foaming.

The skin material is preferably made by laminating a synthetic resin film on one surface of the cloth (claim 2).

The skin material may be made of only a synthetic resin film (claim 3).

The main component of the synthetic resin film may be polyurethane (claim 4).

The synthetic resin film preferably contains a minute amount to 0.15% by weight of a wax as a lubricant (claim 5).

Further, it is preferable that the surface of the synthetic resin film is subjected to corona discharge treatment so that the wetting index becomes 34 dyn / cm or more (claim 6).

[0016]

[Function] After the synthetic resin film surface of the skin material having the synthetic resin film containing a lubricant on at least one surface is subjected to corona discharge treatment, the synthetic resin film surface is made to be an inner surface so as to follow the inner surface of the mold in the molding die By molding and then injecting the unfoamed undiluted solution of the foaming synthetic resin into the molded skin material in the same mold to foam the same, a uniform foam body without cell roughness is formed on the inner surface of the skin material.

Regarding how the inner surface of a synthetic resin film containing a lubricant is subjected to corona discharge treatment, the surface of the film is changed, and why the influence of the lubricant is suppressed by the current situation. However, although it has not been clarified yet, the following is considered.

(1) When corona discharge is applied to a weak layer on the film surface, electrons collide with each other, and the electron energy partially destroys the bond between elements to form an unstable molecule.

This unstable molecule is combined with oxygen decomposed by ozone having a strong reducing property generated at the time of corona discharge, and the molecular structure of the film surface becomes complicated, which prevents the lubricant from protruding to the surface. To be

(2) A large amount of electrons collide with the film surface to electrically ionize the film surface, strengthening the bond between the foam material and the film, and reducing the influence of the lubricant. .

(3) By performing corona discharge, the collision portion is melted by the energy when electrons collide with the film surface, and fine recesses are formed on the film surface.
This physical change strengthens the bonding between the foam material and the film, and the influence of the lubricant is less likely to occur.

[0022]

Embodiments of the manufacturing method of the present invention will be described below with reference to the accompanying drawings. 1 to 5 show a first embodiment of a method of manufacturing a seat portion (or backrest) of a chair to which the present invention is applied in the order of steps.

In FIG. 1, (1) is a roll wound with a thermoplastic synthetic resin film (2) containing a lubricant. As the lubricant, known waxes that have been conventionally contained in synthetic resins for the purpose of facilitating handling after die cutting or molding can be used, and the content thereof is, as described later, corona discharge treatment. However, it is preferable that the amount is from a minute amount to 0.15% by weight. If this value is small, the slipperiness of the synthetic resin film (2) will be poor and handling will be inconvenient, and if this value is large, cell roughness will increase.

The main component of the synthetic resin film (2) is preferably a synthetic resin such as polyurethane, polyethylene or polypropylene. When the later-described foam (13) is made of polyurethane foam, it is preferable to use polyurethane in consideration of its adhesiveness.

Reference numeral (3) is an electrically grounded dielectric roller, and reference numeral (4) is an electrode disposed in proximity to and insulated from the dielectric roller (3). And dielectric roller
A high frequency and high voltage are applied between (3) and the high frequency oscillator (5), and the air between them is dielectrically broken down and ionized to generate corona discharge. During corona discharge, roll above
By passing the synthetic resin film (2) unwound from (1), one surface of the synthetic resin film (2) is treated.

In the case of such a film treatment by corona discharge, the maximum factors that determine the treatment effect are the unit area of the original fabric and the treatment power (active power) with respect to time. When the film (2) is treated, it may be relatively low, for example, about 5 to ²⁰ W / m ² / min. This is because, as will be described later, when the processing effect required in this embodiment is represented by a wetting index conventionally used as a value representing this type of processing effect, it is a relatively small value of about 34 dyn / cm. Because it is good.

In this embodiment, the corona discharge treatment device (6) comprises a dielectric roller (3), an electrode (4) and a high frequency oscillator (5). A device may be used. In particular, it is preferable to use a thyristor type.

Detailed conditions such as the applied voltage and frequency, the feed rate of the material and the specific working procedure are determined based on the material of the synthetic resin film, the feed width, etc. Since various kinds of information are already known, detailed description thereof will be omitted.

Next, as shown in FIG. 2, the synthetic resin film (2) having a corona discharge treatment of an appropriate strength on one surface is used as a skin material, and a recess having a desired shape is formed on the upper surface as shown in FIG.
Place on a metal mold (7) for vacuum heat molding in which (8) is formed with the surface subjected to corona discharge treatment facing upward, and further press the holding frame (10) from above. , The peripheral edge of the mold (7) and the synthetic resin film (2) are airtightly adhered.

In this state, the synthetic resin film (2) is heated by hot air, an electric heater (not shown) or other heating means, and is punched in the mold (7) so as to communicate with the recess (8). If it is exhausted from the exhaust hole (9), the synthetic resin film (2)
Is molded so as to be in close contact with the inner surface of the recess (8) of the mold (7) as shown in FIG. The synthetic resin film (2) may be molded only by a vacuum suction action without using a heating means or by a molding means such as a press. If the heating means is not used, the synthetic resin film (2)
Need not be thermoplastic.

Next, the holding frame (10) is removed and, as shown in FIG. 3, inside the synthetic resin film (2) formed in a concave shape,
When a desired amount of unfoamed undiluted solution (11) of foamed synthetic resin such as foamed polyurethane is injected and the opening surface is closed by the upper lid (12) and then foamed, a synthetic resin film is obtained as shown in FIG.
A foam (13) is formed in the recess of (2).

When molding this foam (13), in the conventional method, due to the effect of a lubricant such as wax contained in the synthetic resin film (2), cell roughening occurs in a portion close to the synthetic resin film (2). In addition to the poor adhesion between the foam (13) and the synthetic resin film (2) which is the skin material, the foam (1
Although the property of 3) is deteriorated, if the surface of the synthetic resin film (2) that is in contact with the foamed body (13) is subjected to corona discharge treatment in advance as in the present example, the above-mentioned effects of the present invention are obtained. As is clear from the above reason and the experimental examples described later, it is possible to suppress the occurrence of cell roughness,
Adhesion between (2) and the foam (13) can be improved, and a homogeneous foam (13) with good properties can be obtained.

Next, the upper lid (12) is removed, and the synthetic resin film (2) is released from the mold (7) together with the foamed body (13). As shown in FIG. A foam molded article (14) covered with a skin material made of only the resin film (2) is formed. It should be noted that the greater the amount of lubricant contained in the synthetic resin film (2), the easier the mold release.

After that, as shown in FIG. 5, the periphery of the synthetic resin film (2) is folded back inward, and the seat plate (15) is attached to the back surface (top surface in FIG. 5) of the foamed molded body (14). For example, the seat of the chair
(Or backrest) is formed.

6 and 7 show a second embodiment of the present invention. In the second embodiment, as shown in FIG. 6, the same synthetic resin film (2) as in the first embodiment is provided with a highly stretchable cloth (21) on the side not subjected to the corona discharge treatment. The laminated sheet (22) in which (1) is laminated is used as a skin material to cover the foamed body (13).

In order to manufacture the laminated sheet (22), it is preferable that one surface of the synthetic resin film (2) is subjected to corona discharge treatment in the same manner as described above, and then the cloth (21) is laminated on the other surface. After laminating the cloth (21) first, the surface of the synthetic resin film (2) opposite to the cloth (21) may be subjected to corona discharge treatment.

Laminated sheet (22) manufactured in this way
2 with the surface treated by the corona discharge facing upward.
7 and by carrying out the same work as in the case of the first embodiment below, as shown in FIG. 7, a skin material (laminated layer) whose outer surface is a cloth (21). A foam molding (23) covered with the sheet (22) is formed. Also in this case,
When the unfoamed undiluted solution of the foaming synthetic resin is injected into the inner surface of the concave-shaped laminated sheet (22) for foaming, the laminated sheet (2
By subjecting the inner surface of 2) to corona discharge treatment in advance, it is possible to suppress the occurrence of cell roughness, as in the case of the first embodiment.

Experimental Example In the manufacturing method as in the first embodiment, the amount of the lubricant contained in the synthetic resin film (2) was 0.1% or 0.15%.
And 0.2% (both are weight ratios; the same applies below), and the degree of cell roughness was compared by changing the strength of corona discharge treatment for each.

Here, as a method for judging the strength of the corona discharge treatment, the wetting index according to JIS K6768 "Wetness test method for polyethylene and polypropylene film" on the treated surface after treatment was used.

As a criterion for cell roughness, a cell roughness evaluation table shown in Table 1 which was originally prepared was used.

[Table 1]

The results are shown in FIG. From FIG. 8, if the amount of the lubricant is 0.15% or less, the wetting index is 34 dy.
It can be seen that the cell roughness does not occur when the corona discharge treatment of n / cm or more is performed.

The wetting index of 34 dyn / cm is
Wetting index for polyethylene printing is about 38 dy
It is n / cm and the wetting index for printing on the polypropylene film is 37 to 38 dyn / cm, and it is clear that the corona discharge treatment is a relatively weak treatment. It is significant that such a weak treatment can effectively prevent cell roughness.

[0043]

According to the apparatus of the present invention, the surface of the synthetic resin film of the skin material, which is in close contact with the foam material, is subjected to corona discharge treatment in advance, so that the lubricant contained in the synthetic resin film can be formed when the foam material foams. The function of the foam-forming agent for stabilizing the foam formation in (2) is not obstructed, and the occurrence of cell roughness in the portion close to the film surface can be prevented or suppressed.

Therefore, it is possible to prevent the generation of defective products due to the roughening of the cells of the foam, to prevent the waste of the material including the expensive upholstery material, and to stabilize the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing a situation of corona discharge treatment of a synthetic resin film according to a first embodiment of the present invention.

FIG. 2 is likewise a vertical sectional front view showing a state before vacuum heat molding.

FIG. 3 is likewise a vertical cross-sectional front view showing a situation when the foam is injected and foamed after completion of the vacuum heat molding.

FIG. 4 is likewise a vertical cross-sectional front view of a foamed molded product that is released after the completion of foaming.

FIG. 5 is likewise a vertical cross-sectional front view of a state in which the seat is completed as a seat portion.

FIG. 6 is an enlarged vertical sectional front view of a part of a laminated sheet used as a skin material in the second embodiment of the present invention.

FIG. 7 is likewise a vertical sectional front view of the completed foamed molded body.

FIG. 8 is a diagram showing the relationship between the wetting index and the degree of cell roughness in the experimental results.

[Explanation of symbols]

 (1) Roll (2) Synthetic resin film (skin material) (3) Dielectric roller (4) Electrode (5) High frequency oscillator (6) Corona discharge treatment device (7) Mold (8) Recess (9) Exhaust Holes (10) Holding frame (11) Unfoamed synthetic resin unfoamed solution (12) Upper lid (13) Foam (14) Foam molded body (15) Seat plate (21) Cloth (22) Laminated sheet (23) Foam molded body

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location // B29K 75:00 105: 04 B29L 9:00 C08L 75:04 (72) Inventor Katsumi Kashihara Nagoya 5-32, Sakae, Naka-ku, Ozaki Light Chemical Co., Ltd. (72) Inventor Masateru Iida 5-1-2, Sakae, Naka-ku, Nagoya City Osaki Light Chemical Co., Ltd.

Claims (6)

[Claims] 1. A surface of a skin material having a synthetic resin film containing a lubricant on at least one surface thereof is subjected to corona discharge treatment, and then the synthetic resin film surface is taken as an inner surface to extend along the inner surface of the mold. A method for producing a foam-molded article covered with a skin material, which comprises molding in the same manner and then injecting an unfoamed undiluted solution of a foamed synthetic resin into the molded skin material to cause foaming. 2. The method for producing a foam-molded article covered with a skin material according to claim 1, wherein the skin material is formed by laminating a synthetic resin film on one surface of a cloth. 3. The method for producing a foam-molded article coated with a skin material according to claim 1, wherein the skin material is made of only a synthetic resin film. 4. The method for producing a foam-molded article coated with a skin material according to claim 1, wherein the synthetic resin film has a main component of polyurethane. 5. A foamed molded article coated with a skin material according to any one of claims 1 to 4, wherein the synthetic resin film contains a wax content from a minute amount to 0.15% by weight as a lubricant. Manufacturing method. 6. The foam molding coated with the skin material according to claim 1, wherein the synthetic resin film surface is subjected to corona discharge treatment so that the wetting index is 34 dyn / cm or more. Body manufacturing method.