JPH03185115A - Heat-fusible conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain the subject conjugate fiber having excellent heat-fusibility and adhesivity to paper or metal plate by carrying out conjugate spinning of a specific ethylenic copolymer and a crystalline polypropylene in such a manner as to get a conjugated fiber having the ethylenic copolymer continuously extending on the fiber surface in longitudinal direction. CONSTITUTION:The objective fiber is produced by carrying out side-by-side or sheath-core conjugate spinning of (A) a crystalline polypropylene having a melt flow rate of >=10g/min at 190 deg.C and (B) an ethylenic copolymer having a melt flow rate of >=20g/min at 190 deg.C and produced by copolymerizing (i) 5-60wt.% of an acrylamide comonomer expressed by formula (R1 is CH3 or H; R2 and R3 are 1-4C alkyl; n is 2-4) and (ii) 95-40wt.% of ethylene. The spinning is performed in such a manner as to expose the component B on a part of the fiber surface in a state continuously extending in longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat-fusible composite fiber that can be well bonded to paper, metal, etc.

[Conventional technology]

A polyolefin-based polyolefin obtained by composite spinning in which the high melting point component is crystalline polypropylene, the low melting point component is high density polyethylene, low density polyethylene, or linear low density polyethylene, and the low melting point component forms the fiber surface. Heat-fusible composite fibers are well known in the art. Such fusible conjugate fibers are usually heat-treated in a web state near the melting point of a low-melting point component to form a nonwoven fabric in which the contact points between the fibers are fused together. However, this nonwoven fabric has weak adhesion to other materials such as paper and metal, making it difficult to combine it with other materials to form a composite material. Although it is possible to use a binder for adhesion to other materials, no inexpensive adhesive with sufficient adhesion to polyolefin is known.

In order to increase adhesive strength with other materials, polypropylene modified with unsaturated fatty acids (Japanese Patent Publication No. 55-271774) or polyethylene modified with unsaturated carboxylic acids (Japanese Patent Publication No. 1-92415) is used as a heat-sealing component. Several attempts have been made, but none of them have yielded satisfactory results.

[Problem to be solved by the invention]

The purpose of the present invention is to improve the conventional heat-fusible conjugate fibers and provide a polyolefin-based heat-fusible conjugate fiber that has excellent not only heat-bondability between fibers but also excellent adhesion to other materials. do.

[Means to solve the problem]

As a result of intensive research to solve the above problems, the present inventor has found that
The present invention was completed based on the knowledge that the desired objective could be achieved by composite spinning using the specific polypropylene and specific ethylene copolymer shown below.

That is, in the first invention of the present application, the first component has a melt flow rate of 190°C.
Crystalline polypropylene with Q i /m1rr or more,
1. The second component is -Crest hole CH3=OR, -00-NH-
(CH2)n-NR2R3 (wherein R1 is H or CH3
; R,, R, is an alkyl group having 1 to 4 carbon atoms: n is 2
It consists of 5-60% by weight of an acrylamide-based comonomer (integer of ~4) and 95-40% by weight of ethylene, and the melt flow rate at 190°C is 20 g/
ml or more, or a mixture of an ethylene copolymer containing 50% of this ethylene copolymer and polyethylene, wherein the second component extends at least part of the fiber surface. This is a heat-fusible conjugate fiber made by spinning both components in a parallel or sheath-core type so that they are continuously formed in the widthwise direction.

In the second invention of the present application, the first component has a melt flow rate of 1 at 190°C.
Q: With crystalline polypropylene of 97m or more! +shi, the second component is -mona〇H,=OR1-00-NH-(C
H2) n-NR2R3 (wherein R1 is H or CH3;
R,, R3 is an alkyl group having 1 to 4 carbon atoms; n is 2 to 4
an acrylamide comonomer represented by (an integer of) 5 to
Consisting of 60% by weight and 95-40% by weight of ethylene,
Melt flow rate at 190℃) is 2ON/+lI
! The above ethylene copolymer, or a mixture of an ethylene copolymer containing 50:ii% or more of this ethylene copolymer and polyethylene, both components are introduced into respective extruders, and the first The spinning temperature of the components is 170~2
Under the conditions of 20°C and a spinning temperature of the second component of 135 to 200°C, both components are spun in a parallel type or sheath-core type so that the second component forms at least a portion of the fiber surface continuously in the length direction. This is a method for producing heat-fusible conjugate fibers, which is characterized by conjugate spinning.

In the present invention, the first component of the heat-fusible composite fiber is a propylene homopolymer obtained using a Ziegler-Natsuta catalyst, or a copolymer containing propylene as the main component and an α-olefin such as ethylene or butene-1. A polymer with a melt flow rate of 10f at 190°C
! /11Lil! The above crystalline polypropylene is used. The melt flow rate of crystalline polypropylene is IOg
/excitation, the spinning temperature of the second component (135
~200℃) under conditions that do not adversely affect the temperature (170~22℃).
(0°C), it becomes difficult to spin.

The general formula % formula % used as the second component of the heat-fusible conjugate fiber in the present invention (wherein, R1 is H or CH3; R,, R, is carbon number 1
~4 alkyl group; n is an integer of 2 to 4) 5 to 60% by weight of an acrylamide comonomer and ethylene 9
A copolymer with 5 to 40% by weight is disclosed in JP-A-63-1170.
Among the compounds shown as dyeability improvers for polyolefins, such as in No. 48, those have a melt flow rate of 1097M or more at 190°C. The copolymer of an acrylamide comonomer and ethylene represented by the above-mentioned hole has poor heat resistance stability, and its spinnability decreases due to thermal decomposition at a normal polyolefin spinning temperature (around 250° C.).

However, the melt flow rate at 190°C is 1 (1
If 7 or more fibers are selected and used, spinning can be performed at 170 to 200°C, which is below the thermal decomposition temperature.

If the acrylamide comonomer content in this copolymer is less than 5% by weight, the adhesion of the fiber to other materials will be insufficient, and if it exceeds 60% by weight, the spinnability will be significantly reduced.
It is also difficult to produce copolymers.

In accordance with the present invention, the second component of the heat-fusible composite fiber includes:
The copolymer of the acrylamide comonomer and ethylene can be used as a mixture with polyethylene. As the polyethylene, high density polyethylene, low density polyethylene or linear low density polyethylene can be used, provided that the melt flow rate of the mixture at 190°C is 20 or more. If the proportion of polyethylene in the mixture exceeds 50% by weight, the resulting heat-fusible composite fiber will have poor adhesion to other materials, so the proportion of polyethylene in the second component should be less than 50% by weight. There is a need.

According to the present invention, the first component and the second component are arranged in a parallel type, or in a sheath-core type or eccentric sheath-core type in which the first component is a core component and the second component is a sheath component, and composite spinning is performed. By doing so, a composite fiber is obtained in which the second component forms at least a portion of the fiber surface continuously in the length direction. 1st component and 2nd component
The ratio with the components (composite ratio) is 30:70 to 70:3
A range of 0 is preferred. If the first component is less than 30t4, the fiber strength will be insufficient, and if the second component is less than 30%, the adhesion to other materials will be insufficient, both of which are unfavorable.

The spinning temperature of the second component is selected from the range of 135-200. If the spinning temperature of the second component is less than 135°C, the spinnability of the second component will be insufficient, and if it exceeds 200°C, thermal deterioration of the second component will occur, both of which are not preferred. The spinning temperature of the first component is selected from the range of 170 to 220°C. If the spinning temperature of the first component is less than 170°C, the spinnability of the first component will be insufficient, and if it exceeds 220°C, it will be difficult to control the spinning nozzle temperature of the second component to 200°C or less. In the evening, things weren't looking good.

〔Example〕

The present invention will be specifically explained with reference to Examples and Comparative Examples.

(Spinning test) Examples 1 to 7, Comparative Examples 1 to 6 Copolymers of various polypropylene, polyethylene, and acrylamide comonomers shown in Table 1 and ethylene were prepared with a pore size of 0.8 N+31 and a pore number of 100. Using a sheath-core composite nozzle, the spinning temperature shown in Table 1 was used, extrusion was 1140 g/++m, and take-off speed was 655 m/T! uA, an undrawn yarn with a single yarn fineness of 11 denier was obtained. This undrawn yarn was drawn 3.67 times at a drawing temperature of 50° C., crimped, and then cut into a fiber length of 51 ioa to obtain a fabric with a single fiber fineness of 4 denier.

The evaluation method for spinnability was as follows: during continuous spinning for 10 minutes, no yarn breakage occurred at all as good, and yarn breakage occurred once or more as poor. Table 1 also shows the evaluation of spinnability.

(Adhesion test) The fabrics obtained in Examples 1.5 to 7 and Comparative Example 6, and polyethylene (190°C, melt flow rate) 3O
N/10m) as a sheath component and polypropylene (230℃,
Composite fiber fabrics (reference example) with a melt flow rate of 25Ii/m1R) as a core component, a single yarn fineness of 3 denier, and a fiber length of 51m were each made into a carded web with a basis weight of 501/m, and thermal calendering (linear pressure of 6ky/art) was used. ) The nonwoven fabric had a breaking strength of 5 kg/5 or more. The respective calender temperatures are shown in Table 2. These nonwoven fabrics were each made of kraft paper (basis weight 111/m2).
, copper plate (thickness 0.5m), brass plate (thickness 0.5m)
ml! ), placed on an iron plate (thickness: 0.5 JEI) and an aluminum plate (thickness: 0.5 m), and hot pressed at 140° C. and 5 to 9/crA for 1 minute to obtain a laminate. Each of the resulting laminates has a width of 5 cnL and a length of 20 c! Five sample pieces of IL were cut and peeled, and the peel strength was measured according to JI8 L 1086 (adhesion test method 6.19 (peel strength)). The measurement results are shown in Table 2.

〔Effect of the invention〕

As is clear from the data shown in Table 1 and Table 2, the heat-fusible composite fiber of the present invention has good spinnability,
Moreover, compared to the conventional composite fiber shown as a reference example,
It has outstanding adhesion to paper and metal plates, making it useful as a composite material with these other materials.

that's all

Claims (2)

[Claims] (1) The first component is crystalline polypropylene with a melt flow rate of 10 g/min or more at 190°C, and the second component has the general formula CH_2=CR_1-CO-NH-
(CH_2)_n-NR_2R_3 (where R_1 is H
or OH_2; R_2 and R_3 are alkyl groups having 1 to 4 carbon atoms; n is an integer of 2 to 4); 5 to 60% by weight of an acrylamide comonomer; and 95 to 40% by weight of ethylene; An ethylene copolymer having a melt flow rate of 20 g/min or more, or a mixture of an ethylene copolymer containing 50% by weight or more of this ethylene copolymer and polyethylene, in which the second component is on the fiber surface. A heat-fusible composite fiber formed by spinning both components in a parallel type or sheath-core type so that at least a portion of the fiber is continuous in the length direction. (2) The first component is crystalline polypropylene with a melt flow rate of 10 g/min or more at 190°C, and the second component has the general formula CH_2=CR_1-CO-NH-
(CH_2)_n-NR_2R_3 (where R_1 is H
or CH_3; R_2 and R_3 are alkyl groups having 1 to 4 carbon atoms; n is an integer of 2 to 4); 5 to 60% by weight of an acrylamide comonomer; and 95 to 40% by weight of ethylene; An ethylene copolymer with a melt flow rate of 20 g/min or more, or a mixture of an ethylene copolymer containing 50% by weight or more of this ethylene copolymer and polyethylene, and both components are extruded in separate extruders. The spinning temperature of the first component is 170-220℃, and the spinning temperature of the second component is 135-220℃.
Heat fusion bonding characterized by composite spinning of both components in a parallel type or sheath-core type under a condition of 00°C so that the second component forms at least a part of the fiber surface continuously in the length direction. Method for producing composite fiber.