JPH0232365B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyester monofilament suitable for weaving screen gauze. The purpose is to provide a polyester monofilament that generates less white powder scum during weaving and provides screen gauze of excellent quality. Polyester monofilaments, especially polyethylene terephthalate monofilaments, have many excellent properties and have traditionally been used for screen gauze.In recent years, they have also entered the fields of electronics and high-end printing, and monofilaments have become finer. , demands for higher strength, improved durability, etc. are increasing. However, when weaving screen gauze using such polyester monofilament,
White powder scum is likely to occur and cause various problems. Problems caused by the generation of white powder scum are especially caused by fineness.
This is common when weaving high-density screen gauze of 250 mesh or more using polyester monofilament of 20 denier or less as the warp thread. This white powder scum is generated by repeated rubbing of the reed, and when using polyester monofilament with a fineness of more than 20 denier, the reed width (distance between the reeds and the cross-sectional diameter of the filament) is wide. The degree of abrasion is light and its influence is small. Moreover, since the fineness is high, no actual damage to the gray fabric due to the generated white powder scum is observed. However, when using polyester monofilament with a fineness of 20 denier or less, the reed spacing is usually smaller than the cross-sectional diameter of the filament.
Because the filament is repeatedly subjected to strong abrasions, the surface is severely damaged and white powder scum is often generated. Therefore, this white powder scum clogging causes warp breakage and warp streak spots on the gray fabric, resulting in a significant deterioration in both quality and production efficiency. In order to solve this problem, the applicant of the present application previously proposed a polyester monofilament having at least 30 hemispherical and/or semiellipsoidal convex portions/ ^100μ2 on the fiber surface (Japanese Patent Application No.
No. 120676). However, although this method makes it possible to obtain a monofilament for screen gauze with less friction and less scum, the monofilament cannot be used because it contains an amorphous and non-reactive polymer or silica gel in the polyester. The tensile strength, elastic recovery power, and durability of the resulting screen gauze decrease, while the fiber-to-fiber friction coefficient decreases and the screen becomes extremely smooth, making it difficult to spin or stretch. Problems arise in that the twill comes off in the package cage and the winding appearance collapses. In order to solve the above-mentioned drawbacks, the inventor of the present invention has made repeated studies and found that by attaching particulate matter to the surface of the filament, the polyester monofilament used can be made without reducing its inherent strength and elongation. Therefore, it is possible to prevent the generation of white powder scum during screen gauze weaving without degrading the properties of the screen gauze, and without any problems with winding up such as the twill coming off of the package cage, and furthermore, it has adhesiveness to polyester monofilament. It was discovered that by coating with a water-soluble resin, peeling and falling of fine particles during screen gauze weaving can be prevented, and the present invention was achieved. That is, in the present invention, fine particulate matter with an average particle size of 2.0 μm or less is placed on the surface at least 10 ^times per 100 μm2 of surface area.
This polyester monofilament for screen gauze has a fineness of 20 denier or less and is coated with a water-soluble resin that is adhesive to the polyester monofilament. The polyester monofilament referred to in the present invention is primarily a monofilament made of polyethylene terephthalate. However, even if it is a monofilament made of polyester containing ethylene terephthalate as the main repeating unit and a small proportion (usually 20 mol% or less) of a third component other than the terephthalic acid component and ethylene glycol component copolymerized and/or mixed. good. The degree of polymerization of the polyester is such that the intrinsic viscosity measured with an o-chlorophenol solution at 35°C is 0.5 or more,
Preferably, 0.7 to 1.0 is appropriate. Fine particulate matter is present on the surface of the polyester monofilament in the present invention. Examples of the particulate material include, but are not limited to, calcium carbonate, titanium oxide, silica gel, calcium phosphate, polysulfonate compounds, and the like. In order to exhibit the effect of preventing the generation of white powder scum, the particle size of the fine particulate material is 2.0 μm or less, preferably 1.5 μm or less, and the number of fine particles present on the surface of the polyester monofilament is 10 particles/100 μm ² or more, preferably 15 particles/2. It must be 100 μm ² or more. Although the number of fine particles depends on the size of the fine particles, at most 1000 particles/100 μm ² is sufficient. Any method may be used to attach the particulate matter to the surface of the polyester monofilament, and the timing may be either before or after stretching. Such a monofilament may be melt-spun as a multifilament and then split, or may be melt-spun as a monofilament from the beginning. The above polyester monofilament has a fineness of
Targeting monofilaments of 20 denier or less,
The effect is particularly remarkable when monofilaments with a fineness of 5 to 15 deniers are targeted. As mentioned above, if the fineness is greater than 20 denier, even if it is a conventional monofilament, there is no actual harm, and there is no need to attach fine particles to the surface of the monofilament as in the present invention. It is necessary that the surface of the polyester monofilament of the present invention is further coated with a water-soluble resin that is adhesive to the polyester monofilament. By doing so, the adhesion of the particulate material to the monofilament surface is enhanced, the peeling and falling off of the particulate material is reduced, and the effect of preventing the generation of white powder scum is extremely improved. In addition, since a water-soluble resin is used, the resin and fine particles are easily removed during the scouring process after screen gauze weaving, and the surface of the monofilament that makes up the gauze becomes smooth, making it very clear when used for printing. It also has the effect of producing beautiful prints. The water-soluble resin is not particularly limited as long as it has adhesiveness to polyester monofilament and is water-soluble, but from the viewpoint of affinity for polyester monofilament and water solubility,
Most preferred are water-soluble polyesters. Suitable water-soluble polyesters include polyesters consisting of dicarboxylic acids, alkylene glycols and difunctional compounds having SO ₃ M groups (M being hydrogen or a metal ion) and/or polyalkylene glycols. Dicarboxylic acid components are aromatic, aliphatic, and alicyclic dicarboxylic acids, including oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2
-dimethylglutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid,
1,3-cyclopentanedicarboxylic acid, 1,2-
Cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, 2,5-norbornanedicarboxylic acid, 1,4-naphthalic acid, diphenic acid, 4,
Examples include 4'-oxybenzoic acid, diglycolic acid, thiodipropionic acid, 4,4'-sulfonyl dibenzoic acid, and 2,5-naphthalene dicarboxylic acid, and among these, terephthalic acid and isophthalic acid are preferred. As alkylene glycol components, ethylene glycol, propylene glycol, diethylene glycol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2-ethyl-2-butyl-1,3-propanediol, 2,2 -dimethyl-1,3-propanediol, 2-ethyl-2
-isobutyl-1,3-propanediol, 1,
3-butanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,
1,4-cyclohexanedimethanol, 2,2,
4,4-tetramethyl-1,3-cyclobutanediol, 4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'-(2-norbonylidene)diphenol, 4,4'-dihydroxy Biphenol, o-, m- and p-dihydroxybenzene, 4,4'-isopropylidenediphenol,
Examples include 4,4-isopropylidene bis(2,6-dichlorophenol), 2,5-naphthalenediol and p-xylene diol, among which ethylene glycol and diethylene glycol are preferred. Examples of the polyalkylene glycol component include polyethylene glycol, polypropylene glycol, and the like. The role of polyalkylene glycol is to strengthen the bond between the fibers and the water-soluble polyester, and also to impart softness to the water-soluble polyester. Examples of the bifunctional compound component having a _-SO3M group (M is hydrogen or a metal ion) include _-SO3M group-containing dicarboxylic acids, diols, and oxyacids. M is Li ⁺ , Na ⁺ , K ⁺ , Mg ⁺⁺ , Ca ⁺⁺ ,
Examples include Cu ⁺⁺ , Fe ⁺⁺ and Fe ⁺⁺⁺ , with Na ⁺ and Li ⁺ being preferred. As a compound, the −SO ₃ M group is directly connected to an aromatic nucleus, and the general formula is X is a trivalent aromatic hydrocarbon group, Y is a divalent aromatic hydrocarbon group, R is hydrogen or an alkyl group having 1 to 4 carbon atoms, M is hydrogen, Li ⁺ , Na ⁺ , K ⁺ , Mg ⁺⁺ , Ca ⁺⁺ ,
Cu ⁺⁺ , Fe ⁺⁺ or Fe ⁺⁺⁺ , a is 1, 2 or 3. [R is hydrogen, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, M is Na ⁺ , Li ⁺ , K ⁺ , Mg ⁺⁺ , Ca ⁺⁺ , Cu ⁺⁺ ,
Fe ⁺⁺ or Fe ⁺⁺⁺ , a is 1, 2 or 3. ] Specific examples include sulfoisophthalic acid, sulfoterephthalic acid, sulfophthalic acid, or 4-sulfonaphthalene-2,7-
Metal salts such as dicarboxylic acids, 4-sodiosulfophenyl-3,5-dicarbomethoxybenzenesulfonate, 4-lithiosulfophenyl-3,5-
dicarbomethoxybenzenesulfonate and 6-
Sodiosulfo-2-naphthyl-3,5-dicarbomethoxybenzenesulfonate, dimethyl 5-[4-(sodiosulfo)-phenoxy]isophthalate, dimethyl 5-[(sodiosulfo)-phenoxy]terephthalate and 5-[4-( Sodiosulfo)
-phenoxy]isophthalic acid, etc. Among these, sodiosulfoisophthalic acid to which Na metal is bonded is particularly preferred. The composition and ratio of these are not particularly limited as long as the obtained polyester is water-soluble, but a copolymerized polyester of 20 to 40 mol% of sodiosulfoisophthalic acid is desirable. The resulting polyester has an intrinsic viscosity (IV) of 0.15
~0.5, it is a solid and stable polymer at room temperature, and becomes transparent or suspended when dissolved in water or hot water. The polyester has particularly good affinity for polyester monofilaments and forms a strong film on the surface of the monofilaments. Any method can be used to coat the polyester monofilament with a water-soluble resin film that has adhesive properties, and the timing may be either before or after stretching, and the method described above may be used. This may be done at the same time as the particulate matter is deposited or separately. Usually, after dispersing a water-soluble resin and particulate matter that are adhesive to polyester monofilament in a fiber treatment agent, the treatment agent is made into an emulsion of 1 to 15% by weight, and then the dipping method, oiling roller method, etc. Attach by spray method etc. It is sufficient for the amount of the fiber treatment agent deposited to be about 0.1 to 1.0% by weight of the treatment agent's active ingredient based on the fiber weight, but the amount of fine particles dispersed in the fiber treatment agent depends on the number of fine particles on the fiber surface. It is sufficient to mix them so that the number is 10 pieces/100 μm ² or more. Furthermore, the amount of the water-soluble resin may be suppressed to such an extent that the monofilaments coated with the resin do not have adhesive properties; for example, in the case of the water-soluble polyester described in the present invention,
0.5 to 20% by weight of the total active ingredients of the treatment agent is sufficient.
When the processing agent is used in the form of an emulsion, an emulsifier and an antistatic agent can be added as necessary. The polyester monofilament of the present invention has a fineness of 20 deniers or less, and has an average particle size on the surface.
More than 10 particles/100μm2 of 2.0μm or ^less are attached. When screen gauze is woven with a specific amount of fine particles of a specific size on the monofilament surface, the coefficient of kinetic friction between fibers and metal decreases, smoothness improves, and the monofilament surface becomes smoother. It becomes difficult to scrape off, and the generation of white powder scum during screen gauze weaving is greatly reduced. Furthermore, with the conventional polyester monofilament with a flat surface, in order to obtain screen gauze with good tensile strength, elastic recovery power, and durability, the strength of the monofilament was increased to 5.0 g/de or more, and the breaking strength in the loading curve was increased. Young's modulus at 80% part is 60~
When using 140Kg/ ^mm2 , it was not possible to prevent the generation of white powder scum during screen gauze weaving, but with the monofilament mentioned above with fine particulate matter attached to the surface, the strength was 5.0g/de or more, and the loading curve was Young's modulus at 80% of the breaking strength at
Since the generation of white powder scum is prevented even at 60 to 140 Kg/mm ² , there is no problem during screen gauze weaving, and screen gauze with excellent tensile strength, elastic recovery power, and durability can be obtained. The Young's modulus at 80% of the breaking strength in the loading curve is the breaking strength a in the loading curve shown in the figure.
From the tangent line b drawn to the stretching curve at the position of the tensile strength a' at 80% of Young's modulus. Strength is 5.0g/de or more,
This Young's modulus is 60~140Kg/mm ² , preferably 100~
Screen gauze woven using monofilament with a density of 120 kg/mm ² has improved tensile strength and durability, and has a large elastic recovery force, allowing it to instantly return to its original state after being deformed by rolling. Therefore, clear and good printing can be performed. Such products have a strength of 5.0 g/de or more and a Young's modulus of 60 to 60 at the 80% point of breaking strength in the stretching curve.
The polyester filament is 140Kg/ ^mm2 .
A polyester having an intrinsic viscosity of 0.5 or more, preferably 0.7 to 1.0 as measured with an o-chlorophenol solution at 35°C is melt-extruded, treated with a treatment agent that dissolves the water-soluble resin described above and disperses particulate matter, and then forms a fiber. After adhering the fine particle substance and water-soluble resin to the surface, spinning at a spinning speed of about 800 to 1500 m/min, stretching 3.4 to 4.3 times, and then heat setting at 120 to 180°C. Can be done. As explained above, according to the polyester monofilament of the present invention, when used as screen gauze,
It is possible to drastically reduce the occurrence of white powder scum during weaving without causing a decrease in tensile strength, elastic recovery power, or durability, and it is possible to prevent warp breakage and warp streak spots on gray fabric. In addition, clear and good printing can be performed. The present invention will be explained in more detail with reference to Examples below. Reference example Synthesis of water-soluble polyester 40 parts by weight of 5-sodiosulfoisophthalic acid, 60 parts by weight of terephthalic acid, 56 parts by weight of ethylene glycol, and 0.57 parts by weight of catalyst were reacted, and after transesterification, the temperature was raised to 285°C. By conducting a polymerization reaction, a water-soluble polyester having an intrinsic viscosity of 0.183 was obtained. Example 1 After melting polyethylene terephthalate with an intrinsic viscosity of 0.64 measured with an o-chlorophenol solution at 35°C, it was spun at a spinning speed of 1000 m/min.
As shown in the table, silica gel of various sizes was added to give various numbers of adhered particles, and the water-soluble polyester synthesized in the reference example was added to the total active ingredients of the treatment agent.
After being treated with a treatment agent containing 1.0% by weight, it was rolled up. Next, it was stretched to 4.27 times with a roller heated to 83℃, and then stretched to 0.03 times in a slit heater at 160℃.
Set the heat for seconds and roll it up at a speed of 600 m/min.
Fineness 12 de, strength 5.1 to 5.2 g/de, elongation 28 to 32%,
A monofilament with a 20% elongation elastic recovery rate of 41-43% and a Young's modulus of 117-125 Kg/mm ² at 80% of the breaking strength was obtained. The friction coefficient and white powder generation time of the obtained monofilament were as shown in Table 1. Using the obtained monofilament for the warp and weft, a plain weave of 300 meshes was woven and scoured in a 0.5 g/alkaline bath at 80°C for 20 minutes to obtain a screen gauze with a width of 10 mm and a length of 50 mm. The tear strength of the sample cut into a size was measured using an Instron tensile tester at a head spade speed of 5 cm/min. The results are shown in Table 1.

【table】

[Table] The fiber-to-fiber friction coefficient μFF and the fiber-to-metal friction coefficient μFM were measured by the radar method at a speed of 300 m/min, and the rubbing white powder development time was 5.
16 monofilaments stretched with a tension of 1.5 g were rubbed with a 300 mesh screen gauze weaving reed at a reed speed of 140 strokes/min, and the time until white powder began to be observed with the naked eye was determined. be. The following can be seen from the above results. If the average particle size of the silica gel is larger than 2.0 μm, the coefficient of friction between the fibers will be too low, resulting in loose twill or loose winding during winding, resulting in poor operability. Even if the average particle size of silica gel is smaller than 2.0 μm, if the number of particles is less than 10/100 ^μm2 , the number of particles that continue to adhere to the monofilament surface without peeling off during screen gauze weaving will decrease, and the surface Since there are parts where the powder is squeezed by the reed, a white powder scum is generated in a short period of time. When the average particle size of the silica gel is 2.0 μm or less and the number of particles on the surface of the monofilament is 10 particles/100 μm ² or more, the generation of white powder scum during screen gauze weaving is reduced, and a good screen gauze can be obtained. Comparative Example 1 In Example 1, the experiment was repeated under the same conditions as Experiment Nos. 3, 6, and 10 of Example 1, except that the water-soluble polyester was not used. The results obtained are shown in Table 2.

[Table] From the results, it can be seen that if the material is not coated with water-soluble polyester, the white powder scum prevention effect and screen gauze tearing strength are also reduced.

[Brief explanation of drawings]

The figure is a graph for explaining a method for measuring Young's modulus at a position of 80% of the breaking strength in a stretching curve.

Claims (1)

[Claims] 1. At least 10 fine particles with an average particle size of 2.0 μm or less are attached to the surface per 100 μm ² of surface area, and the polyester monofilament is coated with a water-soluble resin that is adhesive to the polyester monofilament. Polyester monofilament for screen gauze with a fineness of 20 denier or less. 2. The polyester monofilament for screen gauze according to claim 1, wherein the water-soluble resin is a water-soluble polyester.