JPH01132829A - Conjugate monofilament for screen plain gauze - Google Patents

Abstract

PURPOSE:To provide the title monofilaments having specific strength, elongation, etc., having excellent dimensional stability as a material of screen plain gauze for highly precise printed circuit boards and producing no white powder scum when woven, by using a polyester as the core component thereof and a nylon as the sheath component thereof. CONSTITUTION:(A) A polyester such as polyethylene terephthalate as a core component and (B) a nylon such as nylon-6 as a sheath component are used preferably in a volume ratio of the components A:B of 1:5-3:1 to provide the objective filaments having a fineness of <=25 denier, a breaking tenacity of >=6.0g/d, a breaking elongation of 35-15% and a tenacity of >=4.0g/d when elongated by 10%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite monofilament for screen gauze, which is suitable for the industrial field of screen printing, particularly for the production of high-precision printed wiring boards.

Conventional technology Conventional monofilaments for screen gauze are nylon,
Monofilaments made of a single material such as polyester or a monofilament with an antistatic agent added thereto have been used.

However, although nylon has good adhesion with printing emulsions, it lacks dimensional stability and cannot be used for +11 density printing screens such as printed wiring boards, and polyester has a high Young's modulus and has good dimensional stability. However, it had drawbacks such as poor strength and elongation product, generation of white powder scum during weaving, and poor adhesion to printing emulsion, so it was still difficult to use for manufacturing high-precision printing screens. .

Therefore, stainless steel is used for screens for printed wiring boards that require high precision, but stainless steel is not only expensive, but also has problems with elastic recovery and instantaneousness.

Problems to be Solved by the Invention The present invention provides a printing screen for high-precision printed wiring boards that can obtain the high modulus required for gauze without problems such as the generation of white powder scum. An object of the present invention is to provide a synthetic resin monofilament which is suitable for manufacturing a high-precision printing screen, and which also has good adhesion to a printing emulsion.

Means for Solving the Problems The present invention achieves this object by using a synthetic resin monofilament as a special two-component composite monofilament. The composite monofilament has a core-sheath structure using polyester as a core component and nylon as a sheath component, and has a breaking strength of 6.0 g/d or more and a breaking elongation of 35-15χ (preferably 20-30χ)1.
It is characterized by having a strength at 0x elongation of 4.0 g/d or more.

That is, in the present invention, as a means to compensate for the drawbacks of a single material,
By making use of the strengths of each composite monofilament with a core-sheath structure, we have completed a screen gauze material suitable for printed circuit boards that require high precision.

Ideally, the strength-elongation curve would be a straight line, but in the present invention, polyester, which has a poor strength-elongation product but has a high Young's modulus and excellent dimensional stability, is used for the core, and a polyester that lacks dimensional stability is used for the core. ,
By using nylon for the sheath, which has a high strength and elongation product and also has good adhesion to printing emulsion, the excellent properties of both can be effectively utilized, making it possible to use nylon that is superior to ordinary synthetic fibers such as those mentioned above. To provide a monofilament with excellent physical properties that cannot be obtained from a single material.

The polyester used as the core component includes polyalkylene terephthalate, copolymerized polyalkylene terephthalate, and poly(1,4-cyclohexanediol).
including terephthalate), but! ! In order to ensure dimensional stability during heat setting in the processing stage after weaving, it is preferable to use polyethylene terephthalate, polybutylene terephthalate and poly(1,4-cyclohexanediol terephthalate), especially economically. It is best to use polyethylene terephthalate, which is easily available.

In addition, the nylon constituting the sheath component includes nylon 6, nylon 66, nylon 610, nylon 12, aliphatic polyamide such as polyamide condensed with paraaminocyclohexylmethane and dodecanoic acid, polyxylylene adipamide, and polyhexane. Although any aromatic polyamide such as methylene phthalamide can be used, it is preferable to use nylon 6 and nylon 66 from the viewpoint of ease of spinning and economy.

Here, burn picketing and core-sheath peeling are problems in terms of quality requirements for screen gauze, but the countermeasure is to stop heat setting under tension during stretching, and heat set in a relaxed state after stretching. It has been confirmed that by doing this, burn pickets can be significantly reduced, and that peeling of the core and sheath can be prevented by inserting a sleeve into the winding burn.

In this way, by heat setting in a relaxed state after stretching without applying heat cent during stretching, it is possible to manufacture a stable screen that does not change over time, but the heat cent after stretching is 1 to 6%. overfeed rate, especially 3~
Preferably, the drawing is carried out with an overfeed rate of 5% and the drawn yarn relaxed.

In the present invention, the structure of the composite monofilament is such that the sheath component exists continuously over the entire circumference of the cross section and the core component is not exposed, and the cross section may have a normal round cross section shape. The arrangement and shape of the core component are not particularly limited, and can be single core, multicore, round cross section, irregular cross section, concentric, or eccentric, but in order to guarantee dimensional stability, a round cross section that does not disperse stress is recommended. A concentric single-core arrangement or a multi-core arrangement with a round cross section is preferred.

The ratio of the core component to the sheath component is preferably 1:5 to 3:1 in terms of volumetric ratio, particularly 1:2 to 2:1. Further, in the monofilament of the present invention, the fineness is not particularly limited, but it is preferably 25 denier or less.

In addition, in the composite monofilament of the present invention, the reason why the breaking strength is limited to 6 g/d or more is a condition to enable high-tension gauze, which is necessary to enable the manufacture of ultra-precise screens. 'Furthermore, when the elongation at break is 35% or more, it is difficult to obtain a break strength of 6 g/d or more, and the elongation is too large, reducing the dimensional stability of the gauze tension. The following disadvantages are that the elongation is insufficient and problems such as yarn breakage and white powder generation due to shedding movement during weaving, and tearing during gauze tensioning are likely to occur.

Furthermore, the strength at 10% elongation is limited to 4.0 g/d or more due to the dimensional stability of gauze tension, but with conventional polyester filaments, due to the generation of white powder scum, etc. It was not possible to use products of such strength.

In the present invention, by constructing a monofilament with a core-sheath structure made of specific components, it is possible to provide a product that satisfies all of these physical properties that could not be obtained with conventional synthetic fibers.

Example 6 A homogeneous concentric composite filament with a nylon sheath and a polyethylene terephthalate core with a sheath:core volume ratio of 1:1 was spun at a spinning head temperature of 288°C and a spinning speed of 1500 m.
/min, spinneret hole diameter 0.45 mm, and the discharge rate was adjusted so that the fineness after stretching was 20.16.12.9.7 d, and the fibers were stretched and heat-treated under the conditions shown in Table 1.

Table 1 shows a comparison of the yarn quality of the composite monofilament obtained in this example with that of a normal polyester monofilament.

As is clear from the results in Table 1, ordinary screen polyester monofilaments N017.14 and 15
In contrast, composite monofilaments No. 2 to 5 of the present invention were unable to obtain a breaking strength of 6.0 g/d or more, and the strength was low at less than 4 g/d even at 10% elongation.
．． 8-13 and 16-20 are both 6.0 g/
It has a breaking strength of d or more, and a very high modulus with a strength at 10% elongation of 4.0 g/d or more (N001 and 6 are comparative examples).

Using these 20 types of monofilaments, the second
When gauze for printing screens as shown in the table was manufactured, it was found that all products using the composite monofilament of the present invention did not generate white powder during weaving, and screens of high quality could be manufactured stably with excellent workability. Understood.

However, if heat setting is performed during stretching (No. 13), or if heat setting is performed without loosening (No. 11.12), white powder scum and weavability may occur. Although the basic purpose of the present invention can be achieved, there is a problem with the pear shrinkage, making it difficult to obtain a product with sufficient practicality.

Table 2 Evaluation Criteria Punishing ◎ Very good ○ Good ∆ Poor × White powder scum generated on the entire surface ■ Not generated at all 0500 t * / times or more Washing △ 300-500 ts 1 time Washing × 300 Ill 1 time or less Washing weavability ◎ A reversal rate 95% or more ○ A reversal rate 90-95% △ A reversal rate 80-90% × A reversal rate 80% or less Gauze tension properties ◎ Very good O Good △ Poor × Cannot withstand use, dimensional stability ◎ Very good ○ Good △ Unstable× Unstable, overall rating A. Extremely good B for all evaluation items.
Good in all C〃 Bad in either D〃 Extremely poor in either Effect of the invention The composite monofilament of the present invention can be manufactured from relatively inexpensive synthetic resins such as polyester and nylon, and moreover,
While having a moderate elongation at break, it also has excellent breaking strength and high modulus that cannot be achieved with ordinary synthetic resin filaments, making it possible to stably stretch gauze under high tension and with excellent dimensional stability. It can be used to manufacture screens and can also be effectively used to manufacture high-precision printed wiring boards. In addition, since the sheath component is made of nylon,
It has excellent adhesion to the printing emulsion and does not cause the problem of white powder scum during weaving.

Claims (3)

[Claims] (1) A composite monofilament with a core-sheath structure consisting of two components, the core component being polyester and the sheath component being nylon, with a breaking strength of 6.0 g/d or more and a breaking elongation of 35-15% and strength at 10% elongation. A composite monofilament for screen gauze, characterized in that it has 4.0 g/d or more. (2) The composite monofilament according to claim 1, wherein the core-sheath structure is concentric. (3) Claim 1 whose fineness is 25 denier or less
Composite monofilament according to item 1 or 2.