JPS6071711A - Molding fiber - Google Patents

Abstract

PURPOSE:The titled fibers, consisting of a polymer having main repeating structural units consisting of butylene terephthalate, and capable of developing a peak due to the partial melting and recrystallizing in a heating DSC curve by heat treatment and improving the durability of deep-draw molded articles. CONSTITUTION:Molding fibers, consisting of a polymer having >=80mol% butylene terephthalate in repeating structural units, capable of developing a peak due to partial melting and recrystallizing in a heating DSC curve of the fibers by heat treatment, and preferably having the tensile stress x (g/denier) at 20% elongation at 25 deg.C and the tensile stress z (g/denier) at 150% elongation under heating at 130 deg.C satisfying the following relation; x>=0.7 and z<=0.85. USE:Laminated composites on plastic sheets are particularly suitable to facing materials of automotive instrument panels having a high draw ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION A1 Technical Field of the Invention The present invention relates to moldable fibers. More specifically, the present invention relates to a molding fiber that is suitable for forming into a structure having a curved surface when combined with a plastic sheet, and is particularly suitable for deep drawing molded products with a large drawing ratio.

2. Description of the Prior Art and its Problems It is well known that a plastic sheet is formed into a structure having a curved surface as an interior material for vehicles and homes. However, since molded products made of plastic sheets alone have a flat appearance and a cold, hard feel, fabrics are sometimes pasted on the surface of the molded products. In this case 2
In order to attach it to a curved surface, it is necessary to cut and sew the fabric according to the shape, but since this method is inefficient in terms of process, we have developed a composite sheet in which the above fabric is attached to a plastic sheet. It has been proposed to form this composite sheet into a desired shape all at once by thermoforming or vacuum forming.

However, the problem with adopting this efficient molding method is that
This is because the fabric itself does not have sufficient stretchability.

In particular, molded products with a large drawing ratio (deployment magnification) are difficult to apply, or the elongation in the vertical and horizontal directions is unbalanced, making molding difficult. Furthermore, even if the extensibility is increased, if the molded product has a large drawing ratio, the fabric will lift up at the corners and peel due to the force of the fabric trying to return to its original shape after forming. In addition, changes in thickness and density occur between areas where elongation is large and areas where elongation is small during molding, resulting in poor thermoformability.

This deteriorates the appearance and reduces its commercial value.

Such defects are thought to be due to the thermoplasticity of the fabric at the molding temperature, its elongation upon heating, and its high deformation stress.

In order to eliminate such drawbacks, warp knitted fabrics have been proposed in which stretchable fibers such as polyurethane fibers are used in the front and non-stretchable fibers in the back.

However, because this product has a two-layer structure, the front texture and quality are halved, and it is also time-consuming.

There were problems such as high prices. Furthermore, elastic fibers such as polyurethane fibers also have problems in their durability.

Furthermore, a molding fabric using heat-resistant fibers in the pile portion and highly oriented undrawn polyester fibers in the ground portion is also disclosed. Highly oriented undrawn fibers have great extensibility, and therefore formability is considerably improved, but deep-drawn products with large 7 curvatures still have poor appearance at some sharp corners. Not only that, but because the fibers are highly oriented and undrawn, they can easily stretch and break due to minute changes such as changes in tension during knitting, and are also susceptible to fabric dyeing, resin processing, and lamination processing conditions. There were some difficulties in handling, such as unbearable deformation. There were also problems with processing stability, such as holes and easy reproducibility defects after molding.

Although it is possible to use low-melting point fibers for the purpose of imparting easy moldability, they may have difficulties in handling, or may be difficult to use during higher-order processing such as fabric dyeing, resin processing conditions, lamination I, processing conditions, etc. The product could not withstand heat, was deformed, and had a significant deterioration in appearance quality and texture, making it impossible to obtain a product with any commercial value.

In particular, molded products are used as automotive interior materials, especially instrument panels, under various climatic conditions and harsh usage conditions, and for more than 6 to 7 years. resistance, especially aging resistance, and damage to surface quality due to heat cycle treatment.

Partial peeling becomes a problem.

C1 Purpose of the Invention The present inventor has made intensive studies on changes in the thermal properties of fibers due to raw materials, spinning, drawing, and heat treatment, in an effort to provide moldable fibers free of the above-mentioned drawbacks.

By heat-treating thermoplastic fibers, which have been given the characteristic of exhibiting pimples due to partial melting and recrystallization in their temperature-rise DSC curves, the effectiveness of heat-setting of the fibers has been dramatically improved, and it has become possible to achieve the desired results. The present invention was completed based on the discovery that fibers with good moldability can be obtained and the durability of molded products using the fibers can be improved at once.

21 Structure of the present invention, that is, 1 the present invention comprises at least 8 repeating structural units.
A fiber for molding comprising a polymer whose 0 molar ratio is butylene terephthalate, characterized in that upon heat treatment, a peak based on partial melting recrystallization appears in the temperature-rise DSC curve of the fiber, and the above-mentioned molding. A fiber for use, and the tensile stress X (g/d) at 20qb elongation at 25"C and the tensile stress Z (g/d) at 150% elongation under heating at 100°C satisfy the following formulas. A molding fiber characterized by:

X2O3 Z≦085 This is related to.

The materials used in the present invention are not limited to polybutylene terephthalate, but include copolymers of polybutylene terephthalate with isophthalic acid, adipic acid, etc., mixed spun products of polybutylene/terephthalate and other thermoplastic polymers, It may also be a composite spun product with other thermoplastic polymers or a mixed combustible product with other types of materials. The copolymerization ratio, mixing ratio, etc. may be determined as appropriate depending on the type of materials to be copolymerized or mixed within a range that does not affect the purpose of the present invention.
+Usually, it is desirable that the 1d butylene terephthalate component has a mole ratio of 80 or more.

Further, a fabric-like article can be made using the fiber of the present invention, and the form thereof may be arbitrary, such as a knitted fabric or a non-woven fabric.

In addition, its fabric structure is polybutylene lentil thalai-MOO
%, a warp knitted fabric with a so-called two-layered structure using polybutylene terephthalate fibers in the front and stretchable fibers such as polyurethane elastic yarn in the back, or a knitted fabric using the reverse method. In addition,
The structure of the fabric is preferably a warp-knitted fabric that provides balanced elongation during molding.

From the viewpoint of knitting properties of the warp knitted fabric, long fiber glue is preferable, but short fibers may also be used.

It may also be mixed with other fibers in amounts and usage methods that do not impede the molding effect. For example, mixed use with polyester, polyamide, polyacrylic, polypropylene, and polyurethane elastic fibers is exemplified.

It is preferable that the warp knitted fabric is knitted with a coarse gauge so that the back yarn can be easily stretched during forming.

Similarly, the front yarns on the surface are knitted loosely due to the raising treatment that is performed to give a uniform surface appearance, and when the yarn is scraped off during raising, the loops of the knitted fabric are tightened and the second knitted fabric expands and contracts. It is desirable to avoid reducing sexuality. In addition, the elastic fibers of the back yarn may be scraped out during the above-mentioned raising process, so to prevent such scraping, the back yarn is used as a yarn rather than a core yarn wrapped with other yarns or a plied yarn. It is preferable to leave it as is.

The above-mentioned fibers must have excellent heat setting properties and be able to be stretched uniformly with low stress and high sensitivity. Therefore, the fiber must have various properties.

The first characteristic condition is that a peak based on 9-part melt recrystallization should appear during heat treatment.

Fourth, in detail, in order to follow the shape with low stress and high sensitivity, the partial melting temperature range (TR) by heat treatment and the heat of fusion (ΔH) of the microcrystals generated by partial melting recrystallization are each 114- It is necessary that the temperature is 175° C. and 0.15 cal/g or more (however, 2 g is the fiber weight). By satisfying these thermal characteristics, it is possible to provide uniform and balanced elongation with good reproducibility at low temperature and low pressure when deep drawing is performed.

That is, it is preferable that the TR be as wide as possible and the heat of fusion be as large as possible. If the TR range is large, partial melting or breaking occurs at a relatively low temperature, and there is little influence from slight temperature variations during molding, making process control easier. on the other hand.

A large amount of heat of fusion indicates good thermoformability. In other words, the expansion magnification during thermoforming increases, stress decreases, and easy moldability is imparted.

Note that in the present invention, TR and ΔH are measured as follows. That is, the fibers were heated at 150°C for 30
After dry heat treatment for a minute, 5 mg was collected and measured using a differential scanning calorimeter.
The measuring device was a Perkin-E1mer DSC-2 model), and an endothermic-exothermic curve was measured under the conditions of 40°O/min (D heating rate). Calculate TR and ΔH, respectively.

Moreover, the above-mentioned fiber has large extensibility as a second condition of its properties, and when heated n'! J'+ It is necessary to impart properties that allow uniform elongation with low stress.

That is, the tensile stress of the fiber when elongated to 150 cm under heating conditions of 130°C is at least 0.85 g/d or less.

Preferably 0.7 g/d or less and 20 at 25°C
The tensile stress during elongation is set to be 0.7 g/d or more, preferably 08 g//d or more. If the tensile stress at 130°C is out of the above range, there will be a drawback that the moldability will be poor. ! The tensile stress at 25℃ is 0.
．． If it is less than 7 g/a, the morphological stability of the fabric before molding is insufficient, and the durability is also poor, accompanied by a decrease in strength.

By satisfying both the thermal properties and elongation physical properties described above, the maximum drawing ratio is 0.25 or more, and even 0.4
Uniform and balanced elongation of the fabric can be provided when deep drawing is performed to a depth of 0 or more. Here, the drawing ratio is a value given by H/D in a cylindrical molded hole with a diameter DI of 1 m and a length H.

The fiber of the present invention described above has a two-polymer composition, one polymerization condition,
Specification of spinning conditions, dry heat finishing conditions for yarn processing (
By adjusting the dry heat temperature), the above-mentioned thermal properties and elongation physical properties of the forming fiber can be provided. In particular, it is advantageous that the heat history is small.

The molding fiber of the present invention is made into a fabric, which is then attached to a plastic sheet or the like to form a laminated composite, which is then thermoformed or vacuum formed. The heating means may be either wet heat or dry heat. The compatible plastic sheet is polypropylene foam sheet! Polyethylene foam sheet.

Any material that can be molded, such as a vinyl chloride sheet, can be used.

Although the present invention is particularly suitable for deep drawing 9 forming with a large drawing ratio, it is of course also applicable to forming with a small drawing ratio. Therefore, it is particularly suitable as a skin material for automobile instrument panels with a large drawing ratio (expansion ratio), but it is not limited to this, but is also suitable for automobile interiors such as car seats, door trims, console boxes, ceilings, etc. Interior decoration and furniture for other vehicles, aircraft, ships, etc.

It can be widely applied to exterior materials for home appliances, toys, etc.

As mentioned above, the molding fiber of the present invention is made of polybutylene terephthalate, and has specified thermal properties so that it can be easily heat set, and also has specified elongation physical properties so that it can follow deformation with low stress. This allows molding to be performed at low temperatures and pressures.

In addition, since it has great extensibility, it can be uniformly expanded over the entire surface even when deep drawing is performed. Therefore, since the molding can be done at low temperatures, the molded product retains the fiber 841 form on the surface, giving it an excellent appearance and feel.

Because it can be easily molded without the need for excessive pressure during molding, there is no inherent distortion and there is no force to return to the original shape. There is no floating p at the shear corner that is deformed after molding, which is close to zero.

It becomes possible to obtain a molded product with a uniform appearance, excellent texture, and fourth, excellent durability.

Example 1 75 denier, 66 filament polybutylene lenticulate long fiber 8. II was spun at a high speed of 3200 m/min, and then processed into threads for 11 minutes under a thermal history of 0.8 sec at 195°C. The fibers were subjected to dry heat treatment at 150°C for 30 minutes, and a temperature-rising DSC curve was measured. The endothermic-exothermic curve of fiber 8L is like floor 1 in Figure 1.

The melting peak (A) of the microcrystals clearly appears and the heat of fusion of the microcrystals (△H) 0, 64 is generated by the two-part melting temperature range (TR) 114-175°C and the two-part melting recrystallization.
It was cal/g. TR is the best at low temperatures! Sh.

It was wide-ranging.

Using the above-mentioned processed yarn before dry heat treatment, 9 knitting density 4° courses/
An inch warp knitted fabric was knitted. This knitted fabric was dyed at 130°C, dried, raised, and finished at a dry heat temperature of 180°C. The dyed raised knitted fabric was coated with 800g of vinyl chloride paste.
The undercoat was applied to the back side of the knitted fabric at a ratio of m2, and heat-cured to obtain a composite sheet.

After heating this composite sheet to 163℃, the maximum development rate is approximately 29
An automobile instrument panel core made of ABS (acrylonitrile-butadiene-styrene copolymer) resin having a complex curved shape of 5% was vacuum formed. l+1? The shape can be formed easily along the curved shape, there is no sagging in the area with the maximum expansion rate after molding, and the appearance and texture are not much different from the area with the minimum expansion rate (0), resulting in a beautiful finished product. Obtained. Table 1 shows the results of measuring the maximum drawing ratio and peel strength.

In addition, the above-mentioned fiber before dyeing and raising at 20
The stress during elongation (X) is 2.0 g/d, 130°C
The stress (Z) at 150% elongation is 0.80 g/d
Met.

The product of the present invention had excellent moldability and excellent durability as a molded product.

Example 2 After knitting, dyeing, and drying using polybutylene terephthalate long fibers of 70 denier and 24 filaments.

It was brushed and finished at a finishing temperature of 185'a.

The dyed raised knitted fabric was laminated onto a 5 mm thick sheet of polyethylene foam, and the maximum drawing ratio was 04 (M diameter 10
It was heat-molded into a molded body having a concave surface having a concave depth of 41 cm for a cm circle. The molding was carried out easily along the shape of the four parts, there was no lifting of the bottom of the four parts after molding, and there was almost no difference in appearance or texture between the four parts and the flat part (drawing ratio O), and a beautiful molded product was obtained.

When we measured the temperature-rising DSC curve after dry heat treatment at 150°C for 60 minutes on the fibers used in the dyed and raised fabric before molding, the melting peak (A) of microcrystals clearly appeared, and the TR
118-172"C2ΔHO, 60°al, /IX.

X = 1.8 g/d, Z = 0.75 g/d
Met.

Example 6 A 70-denier, 24-filament nylon long fiber was used as the front, and a 75-denier, 66-filament polybutylene terephthalate long fiber was used as the back.

A full set of 28 gauge, two-piece tricot reeds is placed on each reed, giving a swing of 1-'3 to the front/1-1 to the back, and a two-knit density of 50 courses/inch with a front 212/back 1019 runner ratio. A warp knitted fabric was knitted. This knitted fabric was dyed at 98°C, dried, raised, and finished at a finishing temperature of 175°C to 66 wels/inch and 82 coats/inch.

The dyed raised knitted fabric is made of polypropylene foam 3InIIl.
A thick sheet was laminated to obtain a composite sheet (A).

After heating this composite sheet to 155℃, the maximum development rate is approximately 26
It was integrally molded into a car seat (chair) with a 5% curved surface.

The molding is done smoothly and smoothly on the curved surface of the car seat.
A beautiful car seat was obtained with no significant difference in appearance and texture between the region with the maximum expansion rate and the region with a small expansion rate. TR120-170℃ of e and m before dyeing and raising of the above fabric, △H
O, 57 cal/g, X = 1.7 g/d.

Z = 0.72 g/d.

On the other hand, polybutylene terephthalate fiber K, ((instead of polyethylene terephthalate fiber lamp 1) was processed in exactly the same manner as above, and the composite sheet (B) was formed into a composite sheet (B)). However, due to poor moldability, the fabric often "lifted" and the knitted fabric and foam sheet were partially peeled off.T
R140-162℃, △HO, 07cal/g, X =
4.0 g/d, Z ) 2.76/d.

Table 2 shows the results of measuring the maximum drawing ratio and strength before peeling of each of the above composite sheets.

In addition, the endothermic-exothermic curve of this fiber after dry heat treatment is the first
As shown in floor 2 in the figure, it was confirmed that TR and 8 had narrow ranges and small peaks, indicating poor thermoformability.

As is clear from this, it is possible to obtain fibers with excellent thermoformability and durability only with fibers that satisfy the two characteristics of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the endothermic-exothermic behavior of the fiber after dry heat treatment. 1; Molding fiber of the present invention 2: Conventional fiber A: Melting peak of microcrystals Tl + T2' Partial melting temperature range (TR) Patent applicant Toshi Co., Ltd.

Claims (2)

[Claims] (1) A fiber made of a polymer in which at least 80 moles of repeating structural units are butylene terephthalate, characterized in that upon heat treatment, a peak due to partial melting and recrystallization appears in the temperature-rising DSC curve of the fiber. Fiber for molding. (2) Tensile stress X (g
/d) and tensile stress Z (g/d) at 150 modulus elongation under heating at 160°C, each satisfying the following formula. . X2O3 2≦0.85