JP4450708B2 - Monolithic skin material - Google Patents

Description

  The present invention is for integral molding for manufacturing a skin integral molded product such as an automobile interior molded product, which is placed in a mold and is integrally joined to a resin by filling a molten resin. It relates to the skin material.

  Conventionally, molded products with a skin material have been widely used for aesthetics and luxury in automobile interior products etc., after placing the skin material in a pair of male and female molds for molding, after closing the mold, A method is known in which a thermoplastic resin that has been heated and melted is injected from the gate of a mold into the mold, the skin is laminated, and after cooling, the mold is opened and taken out.

And in this method, when the skin material has air permeability, there is a problem that the melted resin oozes out on the surface of the skin layer and deteriorates the texture of the surface of the molded product, thereby reducing the commercial value, and no oozing occurs. Molding at a low pressure, interposing a resin sheet or foam between the skin and the thermoplastic resin, using a backup sheet such as paper, or protection made of the same type of plastic as the thermoplastic resin It has been proposed to use a layered skin material. (For example, see Patent Documents 1 and 2)
After that, in the manufacture of an integrally molded product using a skin with further breathability, the surface of the skin is applied as a mold to prevent the gloss of the molded product surface from rising and the texture from being lowered by the resin exuded from the skin. It has been proposed to use a surface having a concavo-convex surface formed on the surface of a mold in contact therewith. (For example, see Patent Document 3)
JP-A-60-212343 Japanese Patent Laid-Open No. 54-71161 JP 2001-277290 A

  However, woven fabrics and non-woven fabrics are usually used as breathable skin materials in each of the above-mentioned integral moldings. However, these skins are thin and the inner layer surface appears, the followability is poor in injection molding, or they melt during injection molding. There is a problem in that the adhesion between fibers is broken by the heat and pressure of the polymer, and the resin penetrates to the skin surface, or the gap between the fibers becomes large and the molten polymer leaks during injection molding.

  In order to deal with the actual situation as described above and to solve the problem, the present invention particularly searches for and finds the type, fineness, mass per unit area of the nonwoven fabric constituting the skin material, and the adhesive material between the skin and the nonwoven fabric layer. Accordingly, the object is to maintain excellent gloss and texture on the surface of the integrally molded product without causing leakage of resin during injection molding and excellent workability and form retention.

And, in order to achieve the above object, the present invention provides an integral molding skin material comprising a nonwoven fabric laminate formed by laminating a knit skin layer and a short fiber nonwoven fabric layer, and bonding the fibers of the short fiber nonwoven fabric layer to each other. Are melt-bonded by a heat- sealable composite fiber having a side-by-side or core-sheath structure composed of the same or different high-melting fiber and low-melting fiber, and the melting point of the low-melting fiber is in the range of 130 ° C to 210 ° C. Adhesion between the skin layer and the short fiber nonwoven fabric is performed without breaking the adhesion between the fibers of the short fiber nonwoven fabric layer by a heat-fusible fiber sheet having a melting point of 100 ° C. to 180 ° C., and 50% of the laminate at room temperature. The tensile stress is in the range of 150 N / 50 mm to 350 N / 50 mm, and is provided with performance excellent in workability and form retention.

Claims 2 to 3 are specific embodiments of the invention, and claim 2 is characterized in that the knit of the skin layer is a tricot knitted fabric.

Claim 3 is a short fiber nonwoven fabric in which the short fiber nonwoven fabric layer in the invention comprises a high melting point fiber and a heat-fusible conjugate fiber, and the blend ratio is in the range of 80/20 to 95/5 by mass ratio. There, it is characterized in that the basis weight mass is in the range of ^{50g / m 2 ~300g / m 2} .

Claim 4 is a specific embodiment of the heat-fusible fiber sheet used for adhesion between the skin layer and the short fiber nonwoven fabric layer, the sheet has a melting point in the range of 100 ° C. to 180 ° C., and the basis weight is 50 g / it is characterized in that in the range of m ² ~200g / m ^2.

  A preferred example of the heat-fusible sheet is a web-like sheet made of heat-fusible fibers.

The above-mentioned skin material is heated at a predetermined temperature at which a nonwoven fabric laminate in which a short fiber nonwoven fabric layer in which a skin layer and a fiber are bonded with a heat-fusible conjugate fiber is laminated is not broken. Adhesion between the outer skin layer and the short fiber nonwoven fabric is stable and does not cause delamination, and the short fiber nonwoven fabric itself is also composed of a heat fusible composite fiber. Since the gap is securely bonded, the resin does not penetrate to the resin skin surface during injection molding.

  Therefore, during injection molding, there is no fluid wrinkle or skin shift caused by the polymer, and it is possible to obtain an integrally molded product having excellent workability and formability and good appearance.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is an example of a skin material for integral molding of the present invention. In the figure, 1 is a skin layer, 2 is a short fiber nonwoven fabric layer, 3 is for bonding and integrating the skin layer 1 and the short fiber nonwoven fabric layer 2. In the adhesive layer made of the heat-fusible fiber sheet, the skin layer 1, the short fiber nonwoven fabric layer 2 and the adhesive layer 3 form a structure that forms the basis of the skin material for integral molding of the present invention.

Of these, the skin layer 1 preferably has air permeability, and woven fabrics, knitted fabrics, and nonwoven fabrics can be generally used. Tricot knitted fabrics, particularly tricots having a weight per unit mass range of 50 to 200 g / m ² . A knitted fabric is most preferred.

If the basis weight of the tricot knitted fabric is less than 50 g / m ² , the skin is thin and the inner layer surface tends to appear, which is not preferable, and if it exceeds 200 g / m ² , it is sufficient as the skin, but in-mold injection molding In this case, the followability of the epidermis tends to deteriorate, which is not preferable.

  In addition, as a fiber which forms a skin, synthetic fibers, such as polyamide and polyester, are usually used.

  Next, the short fiber nonwoven fabric constituting the short fiber nonwoven fabric layer 2 of the present invention is a mixture of high melting point short fibers and heat-fusible short fibers. Examples of the high melting point fibers include polyester fibers and polyamides. Examples of the heat-fusible fiber include a side-by-side type composed of a high melting point component and a low melting point component of the same or different kind of thermoplastic resin such as polyester resin, polyethylene resin, polypropylene resin, and polyamide resin. Any of the core-sheath type composite fibers may be mentioned.

  Representative examples of this composite fiber include a composite fiber of polyester fiber (melting point of about 250 ° C. to 270 ° C.) and a low melting point polyester fiber (melting point of about 130 ° C. to 210 ° C.), or nylon composite fiber.

  In this case, if the melting point of the low melting point component is 130 ° C. or less, adhesion between the fibers by heat treatment is good, but the adhesion between the fibers is broken by the heat and pressure of the molten polymer at the time of injection molding, and the polymer penetrates to the skin surface. This is not preferable.

  On the other hand, when the melting point of the low melting point component exceeds 210 ° C., it is necessary to increase the temperature of the bonding treatment between the fibers, which is not preferable because it approaches a high melting point region.

  The above-mentioned constituent fibers forming the short fiber nonwoven fabric preferably have a fineness in the range of 1 to 10 dtex. If the fineness is 1 dtex or less, the fine fiber is too thin and thin in the use weight range, and the molten polymer is likely to leak during injection molding. So undesirable.

  On the other hand, if the fineness exceeds 10 dtex, the gap between the short fibers becomes large, and the molten polymer leaks during injection molding, which is not preferable.

  In the present invention, the mixing ratio of the high melting point fiber mixed with the short fiber nonwoven fabric and the heat-fusible fiber is 3% by mass or more, particularly 5% by mass or more in the constituent fibers for moldability. In view of the hardness of the product and the softness of the surface, it is preferably 20% by mass or less, particularly preferably 15% by mass or less.

  Therefore, the blend ratio is preferably in the range of 80/20 to 3/98 by mass ratio, and more preferably in the range of 85/15 to 95/5.

  The high melting point fiber and the heat-fusible fiber are mixed, uniformly mixed and subjected to carding, then subjected to needle punching, and further subjected to heat treatment at a required temperature for a predetermined time by a heat treatment machine. A short fiber nonwoven fabric bonded to the skin layer is obtained.

The weight per unit area of the needle punched nonwoven fabric is preferably 50 g / m ² or more, particularly 80 g / m ² or more in order to prevent see-through and tearing during molding, and from the viewpoint of weight reduction, it is preferably 300 g / m 2. ² or less, particularly 200 g / m ² or less is preferable.

  The heat treatment temperature and treatment time are not necessarily constant depending on the melting point and content of the heat-fusible fiber contained in the nonwoven fabric, but are usually about 90 seconds at a heating temperature of 150 ° C. to 230 ° C.

  The short fiber nonwoven fabric obtained as described above is bonded to the above-described skin 1 as the layer 2 by the heat-fusible fiber sheet 3 and formed into an integrally molded skin.

  The heat-fusible fiber sheet 3 is preferably a spunbond-type adhesive sheet, for example, a web-like fiber sheet, and a sheet that adheres effectively as a point or line bond and does not remain in the form of a layer.

  In addition, as a melting | fusing point range of a sheet | seat, about 100 to 180 degreeC is suitable.

  When the melting point is 100 ° C. or lower, the melting point is low during the injection molding, so that the adhesion between the two layers 1 and 2 of the skin knit and the short fiber nonwoven fabric, which are folded at an angle, is released, and delamination is likely to occur.

  On the other hand, when the melting point exceeds 180 ° C., it is necessary to increase the bonding treatment temperature for integrating the skin layer 1 and the short fiber nonwoven fabric layer 2, and for this reason, the adhesion between the short fibers of the short fiber nonwoven fabric that has been folded at an angle Is not preferable because it is broken.

The preferred basis weight mass of heat-fusible fiber sheet 3 is ^{50g / m 2 ~200g / m 2} , the basis weight mass for integrating skin knit layer 1 and the short fiber nonwoven fabric layer 2 is 50 g / m ² or less The amount of adhesion is not sufficient and delamination tends to occur.

On the other hand, when the mass per unit area exceeds 200 g / m ² , it is necessary to increase the bonding treatment temperature for integrating the skin knit layer 1 and the short fiber nonwoven fabric layer 2. This is not preferable because the bond between the short fibers is broken.

The preferred basis weight mass of heat-fusible fiber sheet 3 is ^{50g / m 2 ~200g / m 2} , the basis weight mass for integrating skin knit layer 1 and the short fiber nonwoven fabric layer 2 is 50 g / m ² or less The amount of adhesion is not sufficient and delamination tends to occur.

On the other hand, if the mass per unit area exceeds 200 g / m ² , it is sufficient to integrate the skin knit layer 1 and the short fiber nonwoven fabric layer 2, and if it exceeds this, the quality becomes excessive and the adhesive layer increases, resulting in completion. The product becomes hard, which is not preferable.

  Adhesion by the heat-fusible fiber sheet 3 for integrating the skin knit layer 1 and the short fiber nonwoven fabric layer 2 is carried out by polymerizing these three layers into a heat bonding device such as a felt calendar. The heating temperature and processing speed are appropriately selected according to each specification.

  The integral molding skin material thus obtained preferably has a 50% elongation stress in the range of 150 N / 50 mm to 350 N / 50 mm at room temperature, and if the 50% elongation stress is less than 150 N / 50 mm, it is injection molded. At times, the integrally molded skin material is soft, causing fluid wrinkles and skin slippage due to the polymer.

  On the other hand, if the 50% elongation stress exceeds 350 N / 50 mm, the injection-molded and integrally molded skin material becomes hard and the entire skin is wrinkled or pulled, which is not preferable.

  Accordingly, it is effective that the 50% elongation stress is 150 N / 50 mm to 350 N / 50 mm as a product characteristic.

  Hereinafter, specific examples will be described.

Example 1
Polyester fiber (PET) with a fineness of 2.2 decitex and a fiber length of 51 mm (melting point: 260 ° C.) 95% by mass, a polyester / low-melting polyester composite fiber (C-PET) with a fineness of 4.4 decitex and a fiber length of 51 mm (C-PET) (low 5% by mass of polyester having a melting point of 150 ° C. is uniformly mixed and then carded to obtain a fiber layer (average fineness: 2.31 dtex) with a basis weight of 150 g / m ^2. number 67 present / cm ^2, similarly depth 7.5mm on the back, end counts 95 present / cm ^2, further depth 5mm on the surface, subjected to needle punching in the number 95 present / cm ² implant, and continuous heat treatment Heat treatment was performed for 90 seconds at a temperature of 180 ° C. using a machine (hot air through method) to obtain a short fiber web.

A spunbond adhesive fiber sheet having a melting point of 140 ° C. (spider web) having a basis weight of 20 g / m ² is placed on the web, and further, a tricot knitted fabric, a basis weight of 92.1 g / m ² and a thickness of is 40 0 [mu] m (surface treatment was intended to put to come to the surface) heat bonding apparatus carrying the bonding temperature 160 ° C. at (felt calender), processing speed 5 m / min, the adhesive process pressure 2.0 Kg / cm ² The skin material for integral molding of this invention was obtained by processing.

Example 2
95% by mass of a polyester fiber (melting point: 260 ° C.) having a fineness of 2.2 decitex and a fiber length of 51 mm, and a polyester / low-melting polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 200 ° C.) 5% by mass is mixed uniformly, and then carded to form a fiber layer (average fineness 2.31 dtex) with a basis weight of 150 g / m ^2. Subsequently, the surface has a depth of 5 mm, the number of driven-in 67 wires / cm ² , the back surface In the same way, the needle punching of depth 7.5mm, driving number 95 / cm ² , and depth 5mm, driving number 95 / cm ² was applied to the surface, and continuously with heat treatment machine (hot air through method) Heat treatment was performed for 90 seconds at a temperature of 230 ° C. to obtain a short fiber web.

On this web, an adhesive fiber sheet (spider web) having a melting point of 140 ° C. having a basis weight of 20 g / m ² is placed, and further, a tricot knitted fabric, a basis weight of 92.1 g / m ² and a thickness of is 40 0 [mu] m (surface treatment was intended to put to come to the surface) heat bonding apparatus carrying the bonding temperature 160 ° C. at (felt calender), processing speed 5 m / min, the adhesive process pressure 2.0 Kg / cm ² The skin material for integral molding of this invention was obtained by processing.

Comparative Example 1
95% by mass of a polyester fiber (melting point: 260 ° C.) having a fineness of 2.2 decitex and a fiber length of 51 mm, and a polyester / low-melting polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 110 ° C.) 5% by mass is uniformly mixed, and then carded to form a fiber layer (average fineness: 2.31 dtex) with a basis weight of 150 g / m ^2. Subsequently, the surface has a depth of 5 mm and the number of driven-in 67 wires / cm ² . In the same way, the needle punching of depth 7.5mm, driving number 95 / cm ² , and depth 5mm, driving number 95 / cm ² is applied to the surface, and continuously with heat treatment machine (hot air through method) A short fiber web was obtained by heat treatment at a temperature of 150 ° C. for 90 seconds.

A spunbond adhesive fiber sheet having a melting point of 140 ° C. (spider web) having a basis weight of 20 g / m ² is placed on the web, and further, a tricot knitted fabric, a basis weight of 92.1 g / m ² and a thickness of is 40 0 [mu] m (surface treatment was intended to put to come to the surface) heat bonding apparatus carrying the bonding temperature 160 ° C. at (felt calender), processing speed 5 m / min, the adhesive process pressure 2.0 Kg / cm ² Four treatments were performed to obtain a skin material for integral molding of the present invention.

Comparative Example 2
85% by mass of a polyester fiber (melting point: 260 ° C.) having a fineness of 2.2 decitex and a fiber length of 51 mm, and a polyester / low-melting polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 110 ° C.) 15% by mass is mixed uniformly, and then carded to form a fiber layer (average fineness: 2.53 dtex) with a basis weight of 150 g / m ² , followed by a depth of 5 mm on the surface and a driving number of 67 / m ² , back surface In the same way, the needle punching of depth 7.5mm, driving number 95 / cm ² , and depth 5mm, driving number 95 / cm ² is applied to the surface, and continuously with heat treatment machine (hot air through method) Heat treatment was performed for 90 seconds at a temperature of 150 ° C. to obtain a short fiber web.

A spunbond adhesive fiber sheet (spider web) having a melting point of 140 ° C. having a basis weight of 20 g / m ² is placed on the web, and further a tricot knitted fabric, a basis weight of 92.1 g / m ² , a thickness is 40 0 [mu] m (surface treatment was intended to put to come to the surface) heat bonding apparatus carrying the bonding temperature 160 ° C. at (felt calender), processing speed 5 m / min, the adhesive process pressure 2.0 Kg / cm ² The skin material for integral molding was obtained by processing.

  Next, the performance of each of the integral molding skin materials obtained in the above Examples and Comparative Examples was compared.

  The results are shown in Table 1.

The weight per unit area, thickness, 50% modulus and moldability in the table were evaluated as follows.
(B) Mass per unit area Determined according to the method described in 8.4.2 of JIS L1096.
(B) Thickness It was measured at a load of 2 KPa according to the method described in JIS L1096, 8.5.1.
(C) 50% Modulus In the tensile test, 50 kg of Tensilon manufactured by Toyo Bald-In Co., Ltd. was used, and the stress at a sample distance of 50 mm was measured at a sample width of 50 mm, a sample length of 100 mm, and a tensile speed of 100 mm / min. Shown as an average of N = 3. Unit is N / 5cm
(D) Evaluation of moldability The nonwoven fabric for integral molding was set in an in-mold mold and the resin was injected to evaluate the shapeability, wrinkles, sheerness, and resin leakage of the nonwoven fabric.

  The skin material for integral molding of the present invention is used for molding automobile interior molded products, electrical product molded products, and the like.

It is a section outline figure of the skin material for integral molding concerning the present invention.

Explanation of symbols

1: Skin knit layer 2: Short fiber nonwoven fabric layer 3: Heat-fusible fiber sheet

Claims (4)

A nonwoven fabric laminate in which a skin layer made of knit and a short fiber nonwoven fabric layer are laminated, and the adhesion between the fibers of the short fiber nonwoven fabric layer is a side-by-side or core sheath made of the same or different high-melting fibers and low-melting fibers The low melting point fiber has a melting point of 130 ° C. to 210 ° C. and is bonded with a heat-fusible conjugate fiber, and the adhesion between the skin layer and the short fiber nonwoven fabric layer has a melting point of 100 ° C. to 180 ° C. The heat-fusible fiber sheet is bonded without breaking the bonding between the fibers of the short fiber nonwoven fabric layer , and the laminate has a 50% stretch stress at room temperature of 150 N / 50 mm to 350 N / 50 mm. A skin material for integral molding excellent in processability and form-retaining properties, characterized in that   The integrally molded skin material according to claim 1, wherein the knit is a tricot. The short fiber nonwoven fabric is composed of high melting point fibers and heat-fusible conjugate fibers, the blend ratio is in the range of 80/20 to 95/5 by mass ratio, and the basis weight is 50 g / m ^{2 to} 300 g. The skin material for integral molding having excellent workability and form retention as claimed in claim 1, which is in a range of / m ² . Heat-fusible fiber sheet has a melting point 100 ° C. to 180 ° C., integrally molded of basis weight mass and excellent processability and shape retention according to claim 1 or 2, wherein the range of 50g / m ² ~200g / m ² Skin material.

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