JP3137792B2 - Method for producing moldable fiber base material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a moldable fiber substrate,
In particular, the present invention relates to a method for producing a moldable fiber base material useful as an interior material for an automobile ceiling material, door trim, rear shell, floor mat, trunk circumference, console, and the like, and also as a molding material for a package tray, a hat, a wall material, and the like.

[0002]

2. Description of the Related Art Conventionally, the above-mentioned interior materials for automobiles include:
Needle punch carpets having the following moldability have been frequently used.

(I) A fiber mat made of polyethylene terephthalate fiber, wool or the like, and polyethylene (melting point 118
C), linear polyester (melting point 140 ° C), polypropylene (melting point 135-164 ° C) and other low-melting fiber mats. Needle punched carpet in which fibers are melted and fibers are bonded.

(Ii) A needle punch carpet obtained by impregnating a fiber mat obtained by needling with an aqueous emulsion of a thermoplastic resin and then drying.

[0005] However, the carpet (i) generally has excellent cushioning properties and light weight, but has insufficient moldability and rigidity. In addition, the carpet (ii) has good cushioning properties, but it is difficult to achieve both heat retention and rigidity, and if the rigidity is increased, the amount of the fiber mat and the amount of the resin aqueous emulsion increase. Therefore, there is a problem that lightness is impaired.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to various interior materials for automobiles, which are excellent in rigidity and cushioning property in a well-balanced manner, have good moldability and heat-resistant mold retention properties, and are excellent in lightness. It is intended to provide a method for producing a suitable fiber base material.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for producing a moldable fibrous base material, comprising a fiber (A) having a melting point of 100 to 200.degree.
A film forming temperature of 40 ° C. or less from one side of a carpet needling a mixed fiber mat comprising 15 to 50% by weight and a fiber (B) having a melting point higher by 40 ° C. or more than the fiber (A) by 85 to 50% by weight. Resin aqueous emulsion (a) is applied, and the film forming temperature is set to 1 from the opposite side of the carpet.
After applying the aqueous resin emulsion (b) at a temperature of not more than 00 ° C.,
Further, the method is characterized in that the fiber (A) is melted but the fiber (B) is heated to a temperature at which the fiber (B) does not melt, and the fiber (A) is pressed and compressed in a molten state.

The needled carpet according to the present invention has a fiber (A) having a melting point of 100 to 200 ° C.
It is a mat which needsled a mixed fiber mat consisting of 85% to 50% by weight of a fiber (B) having a melting point of at least 40 ° C. higher than the fiber (A) by 40% by weight. The fiber (A) preferably has a fiber thickness of 1.2 to 300 denier,
The fiber length is 25 to 150 mm. In addition, fiber (B)
Preferably, the fiber has a thickness of 1.2 to 300 denier and a fiber length of 25 to 150 mm.

If the melting point of the fiber (A) is too low, the carpet shrinks when the applied resin aqueous emulsion is heated and dried, and if the melting point is too high, the melting point of the fiber (B) is reduced. Since the difference disappears and the fidelity of the mold during pressurization and compression decreases, the melting point is 100 to 20.
Fibers in the 0 ° C. range are used. Preferred fibers (A) include polyethylene (melting point 118 ° C.), linear polyester (melting point 140 ° C.), and polypropylene (melting point 135 to 135 ° C.).
164 ° C.).

Further, the fiber (B) is four times more than the fiber (A).
Fibers having a melting point higher than 0 ° C., preferably higher than 70 ° C. are used. If the melting point of the fiber (B) is too close to the melting point of the fiber (A), the fiber (B) undergoes heat shrinkage during pressurization and compression, and the appearance and design as a carpet deteriorate significantly. Specific examples of the fiber (B) used include synthetic fibers such as polyethylene terephthalate and polyamide;
Natural fibers such as cotton, hemp, and wool can be used.

The mixing ratio of the mixed fiber in the needling carpet of the present invention is such that the fiber (A) is 15 to 50% by weight, preferably 20 to 40% by weight, and the fiber (B) is 85% based on the total amount of the mixed fiber. ５０50% by weight, preferably 80-60% by weight. If the proportion of the fiber (A) is too small, in other words, if the proportion of the fiber (B) is too large, the rigidity and heat-resistant shape retention of the obtained fiber base material become insufficient,
Conversely, if the proportion of the fiber (A) is too large, the texture of the fiber base material is impaired, and the cushioning property is reduced.

In order to manufacture the needling carpet, a mixed fiber obtained by sufficiently mixing and opening the fiber (A) and the fiber (B) is supplied to a web forming apparatus, and is stacked so as to have a desired fiber basis weight. A method of needling the web obtained in the vertical direction to entangle the fibers and temporarily fixing them, or various other methods including known methods is used.

The needling carpet thus obtained is then subjected to a deposition temperature of 4 from one side of the carpet.
An aqueous resin emulsion (a) at 0 ° C. or lower is applied, and an aqueous resin emulsion (b) at a film forming temperature of 100 ° C. or lower is applied from the opposite side.

By applying the aqueous resin emulsion (a), the adhesiveness of the fibers can be increased. It is desirable to add a colorant, particularly a pigment, to the aqueous resin emulsion (a). Aqueous resin emulsion (a)
By adding a coloring agent to the fiber, the design of the resulting fiber base material can be enhanced and the commercial value can be improved. The pigment of the colorant to be added to the aqueous resin emulsion (a) may be a color pigment that is usually used for coloring this type of aqueous resin emulsion. In addition, a pigment dispersant, an extender for making the color of the fiber itself inconspicuous, or the like can be added to the aqueous resin emulsion (a) as necessary.

The film forming temperature of the aqueous resin emulsion (a) is 40 ° C. or lower, preferably 20 ° C. or lower. If the film forming temperature is too high, the texture of the obtained fiber substrate is impaired, and the cushioning property is reduced. Even when the film forming temperature of the aqueous resin emulsion (a) is 40 ° C. or higher, the film forming temperature is controlled to 40 ° C. or lower by adding a film forming auxiliary such as texanol, benzyl alcohol, and butyl cellosolve. However, when the carpet is heated or molded in a later step, the film-forming aid may transfer to the surface, so it is not preferable to add too much film-forming aid.

The coating amount of the aqueous resin emulsion (a) is as follows:
The non-volatile content is preferably from 60 to 250 g / m ² . If the coating amount is too small, the fixation of the surface fiber becomes insufficient, and if it is too large, the feeling of the fiber base material is reduced,
Light weight is lost due to an increase in weight, and the effect of improving design properties due to coloring is lost.

The aqueous resin emulsion (b) applied from the opposite side of the needling carpet acts to impart rigidity to the fiber base material. The film forming temperature of the aqueous resin emulsion (b) is 100 ° C. or lower, and preferably higher than the film forming temperature of the aqueous resin emulsion (a).
If the film forming temperature is too high, the moldability decreases and the cushioning property deteriorates.

The amount of the aqueous resin emulsion (b) applied is
It is desirable that the thickness of the impregnated portion with respect to the needle punch carpet reaches 35 to 80% from the surface in view of the balance between the rigidity and the feel of the fiber base material.

The aqueous resin emulsion (a) and the aqueous resin emulsion (b) contain monomers such as styrene, alkyl acrylate, alkyl methacrylate, ethylene, vinyl chloride, vinyl acetate, vinylidene chloride, and a diene compound. It can be produced alone or in various combinations by emulsion polymerization in an aqueous medium according to a known method. In particular, in the case of the resin aqueous emulsion (a), since a resin emulsion having a film formation temperature of 40 ° C. or less can be easily designed, a styrene-alkyl acrylate copolymer, an alkyl methacrylate-alkyl acrylate is used. Copolymer,
A styrene-diene compound copolymer is desirable.

There are various methods for applying the aqueous resin emulsion (a) and the aqueous resin emulsion (b) to the needle punch carpet. For example, a roll method, a doctor knife method, or a spray method may be mentioned as a general method. In order to promote impregnation into a carpet, the carpet may be squeezed through a press roll simultaneously with or after the application.

The needle-punched carpet coated with the aqueous resin emulsion (a) and the aqueous resin emulsion (b) as described above is preferably dried by heating to remove moisture, and dried with the resin applied from both sides. Although a needle punch carpet is used, this heating and drying step is not essential. Various heating and drying methods are possible. A typical heat drying method is to apply a resin aqueous emulsion (a) and then dry and then apply and dry a resin aqueous emulsion (b), or a resin aqueous emulsion (a) and a resin aqueous emulsion (b). ) Are sequentially applied and then dried.

The needle-punched carpet obtained by applying the aqueous resin emulsion (a) and the aqueous resin emulsion (b) as described above, and preferably by heating and drying, is then formed into an aqueous resin emulsion (b). When the fiber (A) is heated to a temperature at which the fiber (A) melts but the fiber (B) does not melt, and the fiber (A) is melted and pressed and compressed in a state where the fiber (A) is melted, an intended fiber base material is obtained. . The heating temperature is, for example, 130 to 250 ° C., preferably 15
0 to 220 ° C., and the degree of compression is such that the apparent density of the obtained fiber base material is usually 0.15 to 0.45 g / cm ^3.
It is the extent that it becomes. If the degree of compression is too high, the resulting fiber substrate will have too high an apparent density, resulting in reduced cushioning and rigidity.If the degree of compression is too low, the resulting fiber substrate will have a low apparent density. And the rigidity becomes insufficient.

[0023]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. “%” And “parts” described in these examples are all based on weight.

Example 1 A polypropylene fiber (melting point: 164 ° C.) having a thickness of 15 denier and a fiber length of about 100 mm (sometimes abbreviated as “PP”) 20%, a thickness of 15 denier and a fiber length of 75 to 1
25 mm polyethylene terephthalate fiber (melting point 26
Fiber mat (540 g) at 80.degree. C. (may be abbreviated as "PET").
/ M ² ) is calculated using a needle of 15-18-32-3RB.
Needling at a rate of 50 pieces per square inch (645 square mm), a wall thickness of about 4.8 mm, and an apparent density of 0.11 g /
It was a needling carpet of cm ³ .

Separately, an aqueous emulsion of a copolymer resin of styrene (30%)-butyl acrylate (68%)-acrylic acid (2%) — the film formation temperature of the emulsion is 0 ° C. or less, and the glass transition temperature of the resin ( Tg) was −18 ° C., and the solid content was 50%｝ (hereinafter referred to as “resin aqueous emulsion I”), and a pigment or the like was blended in the following ratio to prepare a gray colored resin aqueous emulsion.

Resin aqueous emulsion I 100 parts Water 80 parts Titanium oxide 40 parts Calcium carbonate 20 parts Thickener * 1 50 parts Coloring material * 2 5 parts * 1: 2% aqueous solution of hydroxyethyl cellulose * 2: Large Nippon Seika Co., Ltd. Product name EP-510 Black

The above-mentioned needling carpet was roll-coated from one side with the above-mentioned gray aqueous resin emulsion so that the resin content was 150 g / m ² , and styrene ( Aqueous emulsion of copolymer resin of 60%)-butyl acrylate (38%)-acrylic acid (2%) (film formation temperature of 40 ° C., Tg of resin is −18 ° C., solid content 50%)
Was applied by a roll so that the resin content became 250 g / m ² , and then pressure was applied by a nip roll to impregnate the resin emulsion into the carpet.

Next, the resin emulsion-coated carpet was dried by heating at a temperature of 150 ° C. using a cylinder dryer.

The obtained resin emulsion coated and dried carpet is placed in a suction dryer (internal temperature 190 ° C.) for 3 hours.
After that, the polypropylene fiber of the carpet was melted, and the carpet was compressed through a cooling roll in that state to obtain a fiber base material having a basis weight of 940 g / m ² and a wall thickness of 3.2 mm.

Table 1 shows the production conditions of the fiber base material and the results of the following evaluation tests on the obtained fiber base material.

Flexural Strength A sample of 15 cm × 5 cm is taken from the fiber base material, and 5 cm at the center of the span of 10 cm using an Instron type testing machine.
/ Min, and measured the three-point bending strength (maximum bending strength at 5 cm width).

Cushioning A 4 cm × 4 cm sample piece is taken, placed on a table, and a 1 cm × 1 cm pressure terminal is applied at the center of the sample piece with a pressure of 0.2 kg / cm ² using an Instron type testing machine. After loading,
When the pressure was released, the one in which the pressure terminal returned upward was evaluated as having cushioning properties.

[0033] After shaping the base material, the fiber base material is heated with hot air at 190 ° C for 3 minutes, and then heated to 0.35K.
g / cm ² G, with the colored surface facing up, compression molding to form a tray-shaped molded product having a length of 20 cm and a width of 20 cm and a depth of 3 cm. The salmon was examined and evaluated according to the following criteria. ○ ・ ・ ・ Thin with no base ×× Thin with base

[0034] The tray-shaped molded product obtained by the heat resistance of the molded product was left in an oven at 95 ° C for 1 day, and the degree of deformation after removal was visually determined, and evaluated according to the following criteria. ○ ・ ・ ・ No deformation is recognized △ △ Slight deformation × ・ ・ ・ Deformed to the extent that the original shape is not retained

Examples 2 to 3 Comparative Examples 1 to 4 The conditions for producing the fiber base material were changed as shown in Tables 1 and 2, respectively. did. Table 1 and Table 2 show the results of conducting the same tests as in Example 1 for the obtained fiber base materials.
Was as shown in FIG.

[0036]

[Table 1]

[0037]

[Table 2]

As can be seen from Tables 1 and 2, the fibrous base materials of the examples are excellent in rigidity (flexural strength), cushioning property and heat resistance of molded articles (heat-resistant mold-retaining property) in a well-balanced manner.

[0039]

The fibrous base material has rigidity, cushioning properties,
It has excellent balance between moldability and heat resistance (heat retention), and is also excellent in lightness, so that it is suitable for various uses, particularly for interior materials of automobiles.

────────────────────────────────────────────────── ─── Continuing from the front page Examiner Hiroaki Hirai (56) References JP-A-62-299582 (JP, A) JP-A-56-43457 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) D04H 1/00-18/00 D06M 13/00-15/72

Claims (2)

(57) [Claims] 1. A fiber (A) 15 having a melting point of 100 to 200 ° C.
A film forming temperature of 40 ° C. or less from one side of a carpet needling a mixed fiber mat consisting of 85 to 50% by weight and a fiber (B) having a melting point of at least 40 ° C. higher than the fiber (A). A resin aqueous emulsion (a) is applied, and the film forming temperature is set to 100 from the opposite side of the carpet.
° C or lower, but after applying a resin aqueous emulsion (b) higher than the film forming temperature of the resin aqueous emulsion (a), and then applying the resin aqueous emulsion (b) or higher and the fiber (A) Melts, but the fiber (B)
A method for producing a moldable fibrous base material, characterized in that the fiber (A) is heated and pressurized and compressed in a molten state by heating to a temperature at which the fiber does not melt. 2. The method according to claim 1, wherein the aqueous resin emulsion (a) is an aqueous emulsion colored with a pigment.