JPH06257013A - Polycarbonate multifilament - Google Patents

Abstract

PURPOSE:To obtain polycarbonate multifilament suitable as reinforcing fiber especially for various composite materials by subjecting a polycarbonate having a specific repeating unit to melt spinning. CONSTITUTION:A polycarbonate having a repeating unit of the formula as a main repeating unit is subjected to melt spinning to give undrawn polycarbonate multifilament having >=1.5 g/d tensile strength, 100-160% elongation at break and <=3% shrinkage percentage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber for various materials, and more particularly to a polycarbonate multifilament suitably used as a reinforcing fiber for various composite materials.

[0002]

2. Description of the Related Art Polycarbonate has excellent impact resistance, mechanical strength, dimensional stability, electrical characteristics, and light resistance, as well as its transparency, and has the advantage that it has low water absorption. Widely used in electric and electronic parts.

[0003]

However, since polycarbonate has extremely low crystallinity and poor melt spinnability, it has been practically rarely used as a fiber, particularly as a multifilament. . It is an object of the present invention to provide a polycarbonate multifilament that can be widely used in various material fields and the like and can be particularly preferably used as a reinforcing fiber for various composite materials.

[0004]

The present invention has the following constitution in order to solve the above-mentioned problems. That is, in the present invention, the main repeating unit is represented by the following general formula (I).
An unstretched yarn made of the polycarbonate represented by, having a tensile strength of 1.5 g / d or more and a breaking elongation of 100 to
Polycarbonate multifilament having a boiling water shrinkage of 160% and 3% or less, and a yarn obtained by drawing the unstretched polycarbonate multifilament at a temperature of 120 ° C. or less to 2 times or less, having a tensile strength of 2.5
g / d or more, breaking elongation 40% or less, boiling water shrinkage 5%
The above is a polycarbonate multifilament.

[0005]

[Chemical 2]

Since polycarbonate has few crystal phases and most of it is an amorphous phase, thermal properties such as heat resistance are almost governed by the glass transition temperature (T _g ). Therefore, in order to satisfy the heat resistance required in practical use, the polymer constituting the fiber must have a high T _g . The polycarbonate constituting the multifilament of the present invention has a T _g in the vicinity of 150 ° C, and is therefore excellent in heat resistance. Incidentally, T _g can be generally obtained by a differential scanning calorimeter. The heat distortion temperature (HDT) also corresponds to T _g . Polycarbonate is also used in a temperature range below the frozen T _g where the movement of the polymer chain is substantially frozen, so that it is also excellent in dimensional stability.

[0007] Similar to the glass transition temperature, the important physical property required for the polymer constituting the fiber is the elastic modulus. The elastic modulus of polycarbonate does not change much in the temperature range of T _g or lower, and sharply decreases after exceeding T _g , leading to plasticization and fluidization. The flexural modulus of the polycarbonate constituting the multifilament of the present invention is 20,000 kg / in the temperature range of room temperature to 120 ° C.
cm ² or more is maintained, the temperature dependence of the bending elastic modulus is extremely small, and the high elastic modulus is maintained even in a relatively high temperature region such as 80 to 100 ° C.

Further, polycarbonate has a low water absorption rate and a low saturated water absorption. Therefore, there is little deterioration in physical properties under moisture absorption. Therefore, the polycarbonate multifilament of the present invention can be widely used in various material fields in a wide range of environments. The polycarbonate constituting the multifilament of the present invention may be a polymer having a unit represented by the general formula (I) as a main repeating unit, and various modifiers, additives and the like may be blended therein.

When the polycarbonate multifilament of the present invention is used as a reinforcing fiber in various material fields and various composite materials, it is necessary that the number of filaments is 3 or more, preferably 5 or more. It is desirable from the viewpoints of permeability and reinforcing effect.

As a method for producing a polycarbonate multifilament composed of the undrawn yarn of the present invention, a known melt spinning method can be applied. Further, the polycarbonate multifilament comprising the drawn yarn of the present invention,
The unstretched yarn can be easily obtained by stretching the unstretched yarn at a temperature of 120 ° C. or less to twice or less.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples.

Each physical property value in the examples is measured by the following method. The (boiling water shrinkage percentage) yarn of initial length 1 ₀ was immersed for 30 minutes in boiling water, the length 1 ₁ of the subsequent yarn, 1/30 (g
It was measured under the weight of / d) and calculated from the following formula. Boiling water shrinkage percentage (%) = charged (1 ₀ -1 ₁₎ / 1 ₀ × 100% (dry heat shrinkage) initial length 30 min 1 ₀ of yarn in 140 ° C. hot air drier, followed yarn of the length of ₁ 1/3
It was measured under a load of 0 (g / d) and calculated from the following formula. Dry heat shrinkage _{(%) = (1 0 -1} 1) 1 0 × 100%

Example 1 Glass transition temperature is 153 ° C.
The water absorption rate after immersion in water at 23 ° C. for 24 hours was 0.
15% polycarbonate (manufactured by Mitsubishi Kasei Co., Ltd.,
7022A) chips are vacuum dried at 120 ° C. for 14 hours, then melted using an extruder, and a spinning spinneret having 24 circular spinning holes with a hole diameter of 0.3 mm is used, and a spinning temperature of 302
Melt-spinning was carried out at a spinning speed of 1000 m / min at a temperature of ℃, and a multifilament of 150 denier / 24 filament was obtained.
The single filament in the multifilament had almost no fineness unevenness and had a good fiber cross section.

The obtained multifilament has a tensile strength of 1.8 g / d, a breaking elongation of 129% and a boiling water shrinkage of 1.
0% and dry heat shrinkage were 2.2%. Also, 100 ℃
The maximum breaking ratio measured in 1. was 2.24 times.

(Example 2) The multifilament obtained in Example 1 was further drawn at a temperature of 100 ° C by a factor of 1.79, and then passed through a hot plate set at 150 ° C for heat setting. The fiber was wound at a speed of 500 m / min.
The process passability was stable. The resulting multifilament has a fineness of 85.5 denier and a tensile strength of 3.0 g /
d, breaking elongation was 28%, boiling water shrinkage was 11%, and dry heat shrinkage was 16%.

Example 3 Example 3 was repeated except that the draw ratio was changed to 1.90. At this time, although some monofilament winding around the twisting and twisting machine roller occurred and the process passage stability was slightly lowered, stretching was possible. The obtained multifilament had a fineness of 81.2 denier, a tensile strength of 3.2 g / d, a breaking elongation of 22%, a boiling water shrinkage rate of 11%, and a dry heat shrinkage rate of 17%.

Comparative Example 1 The procedure of Example 2 was repeated except that the stretch ratio was changed to 2.10 times. At this time, it was substantially difficult to draw due to yarn breakage.

[0018]

According to the present invention, there is provided a polycarbonate multifilament which has a high elastic modulus even in a high temperature region and has little deterioration in physical properties when absorbing moisture. Such a fiber can be suitably used for various material applications in which physical property deterioration in a high temperature range or under moisture absorption, which has been difficult in the past, poses a problem. Further, since the polycarbonate multifilament of the present invention is a multifilament, post-processing such as knitting and weaving, which has been difficult in the past, becomes extremely easy,
Fiber structures having various morphologies are easily obtained. Therefore, in addition to the excellent properties of the polycarbonate itself, the properties of the fibrous structure can be utilized for a wide range of applications in various industrial fields. Furthermore, the polycarbonate multifilament of the present invention can be preferably used as a reinforcing fiber for various composite materials. It has the effect of improving impact resistance without lowering the elastic modulus of the composite material.

Claims (2)

[Claims] 1. A main repeating unit is represented by the following general formula (I).
An unstretched yarn made of the polycarbonate represented by, having a tensile strength of 1.5 g / d or more and a breaking elongation of 100 to
Polycarbonate multifilament having a boiling water shrinkage of 160% and 3% or less. [Chemical 1] 2. A yarn obtained by drawing the polycarbonate multifilament according to claim 1 at a temperature of 120 ° C. or less to a draw ratio of 2 times or less, having a tensile strength of 2.5 g / d or more and a breaking elongation. A polycarbonate multifilament having a boiling water shrinkage of 40% or less and a boiling water shrinkage of 5% or more.