JPH0351802B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to dustproof clothing. Precision industry, semiconductors,
So-called clean rooms are rapidly developing in the manufacturing process of pharmaceuticals, foods, etc., as well as in hospitals and fields that handle microorganisms, and there is a need for clothing with excellent dust resistance as working clothes in these clean rooms. This is related to dustproof clothing. Conventional technology The required performance of dustproof clothing is (a) high ability to prevent dust from passing through. (b) It is difficult for dust to adhere to it and it comes off easily; (c) it has low dust generation; (d) it has excellent antistatic properties; (e)
Comprehensive performance is required, including excellent chemical resistance. Polyethylene terephthalate is often used as a material for dustproof clothing, as shown in the examples of JP-A No. 55-30436, but it is unsatisfactory from the standpoint of antistatic properties. Problems to be Solved by the Invention From the standpoint of antistatic properties, it is preferable to use antistatic polyester fibers mixed with an antistatic agent. However, polyester generally has insufficient abrasion resistance and tends to break or fibrillate due to friction and generate dust, and this tendency is even more pronounced in antistatic polyester fibers mixed with an antistatic agent. In other words, antistatic properties and dustproof properties have contradictory properties. An object of the present invention is to provide an improved dustproof garment that has excellent antistatic properties and dust generation properties. Means for Solving the Problem The dust-proof clothing of the present invention has (a) a fabric made of polyester continuous filament plain weave, and (b) one of the warp and weft of the plain weave floats (float) and the other sinks. It has a (sinked thread) structure, and (iii) the sunken thread is an antistatic fiber mixed with an antistatic agent, and the floating thread is a non-antistatic fiber. Here, the polyester is not particularly limited, but for example, polyethylene terephthalate (hereinafter referred to as PET), polybutylene terephthalate (hereinafter referred to as PBT), etc.
) and a modified product in which a small amount (51% or less, particularly 10% or less) of a third component is copolymerized or mixed therewith is suitable. The weave structure must be plain weave. Cloth for dustproof clothing requires a structure with few voids from the viewpoint of preventing dust from passing through. The amount of voids can be evaluated by air permeability. Air permeability is JIS L-1096 (1979) A method (Fragile method)
Measured by Air permeability is usually 20 for twill fabrics.
ml/cm ³ /sec or more, but for dense plain weave it is 10
It is easy to set it to ml/cm ³ /sec or less. The air permeability is preferably 10 ml/cm ³ /sec or less, particularly preferably 5 ml/cm ³ /sec or less, and most preferably 2 ml/cm ³ /sec. However, if the air permeability is too low, the feeling of wearing will be poor, so it should be 0.1 ml/cm ³ /sec or more, especially 0.3 ml/cm ³ /sec.
Preferably, the time is seconds or more. Fabrics with low air permeability are made by weaving thin fibers (e.g., single threads of 3 d or less, especially 0.1 to 2 d) at high density, or shrinking with a high shrinkage rate (e.g., areal shrinkage rate of 10% or more, especially 20 to 50%). It is obtained by Furthermore, if necessary, the cloth can be pressed and densified by calendering or the like. Another feature of plain woven fabric is that it has a smooth surface and low dust adhesion, and has excellent abrasion resistance and triboelectric charging properties. As the antistatic agent to be mixed into the antistatic fiber, polyalkylene ethers such as polyethylene oxide, derivatives thereof, and copolymers (e.g., ether/ester block copolymers) are suitable, and they are further added with hydroxyl groups, amino groups, and carboxyl groups. Introducing polar groups such as groups, sulfone groups, and their metal salts,
It is also preferable to mix (combine) an organic compound having a polar group. As the mixed structure, a fluid mixture in which the antistatic agent is dispersed in the form of fine particles (acicular particles in many cases) in polyester (matrix) is also used; As disclosed in the above publication, antistatic agents are those in which the antistatic agent is dispersed in many fine dots (nebula-like) in the cross section of the fiber and has a substantially continuous linear structure in the length direction. It is most preferred because it has excellent antistatic properties and therefore sufficient antistatic properties can be obtained with a small mixing ratio. For example, in the case of polyethylene oxide-based nonionic polymers, it is 1 to 5%.
If 10 to 20% of an ionic compound such as sodium alkylbenzenesulfonate is mixed with the
Approximately 0.1 to 2%, i.e. 1/2 to 1/2 compared to granular mixture
Excellent antistatic properties can be obtained at a mixing ratio of about 1/10. However, polyester fibers mixed with an antistatic agent have a slightly stronger tendency to fibrillate due to friction and the like and cause dust generation than those without the antistatic agent. This tendency is stronger as the mixing ratio of the antistatic agent increases (continuous linear mixing is therefore preferred). In any case, since antistatic fibers often have somewhat poor resistance to abrasion, they are used as sinking yarns, and non-antistatic yarns with excellent abrasion resistance are used as floating yarns. FIG. 1 is a perspective explanatory view of a plain weave used in the present invention. In the figure, 1 is a floating line and 2 is a sinking line.
FIG. 2 is a cross-sectional view of the fabric shown in FIG. 1 in one direction of the floating yarn, and FIG. 3 is a cross-sectional view of the fabric in the second direction of the sinking yarn. In Fig. 2, dotted lines 10 to 10' are the surface of the float;
The dotted line 20-20' is the surface of the precipitated yarn. Surface 10-
The distance A between 10' and surface 20-20' is the "floating height"
It is written as In general, plain weave does not have a structure in which one of the warp and weft sinks and the other floats, and A is often close to zero. However, by changing the tension during weaving and the thickness (hardness) of the warp and weft, the floating height A can be increased to 10 μm or more, especially 20 μm or more.
The thickness can be set to 100 μm, and the probability that the precipitated thread will come into contact with an external object and be damaged can be greatly reduced. That is, by increasing the tension of one of the warp or weft during weaving, it is possible to make it a sink yarn. Similarly, one thread can be made to sink by shrinking it more than the other, or by making it thicker (harder). Furthermore, the floating height can be further increased by combining two or more of the above three methods (high tension, high shrinkage, thick yarn). The float is a non-static polyester fiber. It is desirable that the floating yarn has excellent abrasion resistance. for example,
In addition to homopolymers such as PET and PBT, it is preferable to copolymerize or mix them with a third component to reduce the coefficient of friction or improve wear resistance. Components that reduce the coefficient of friction (for example, the coefficient of friction against metals) include paraffin, polyolefin, polyalkylene ether, compounds with alkyl groups, organic silicon compounds (for example, polyorganosiloxane, etc.), and organic fluorine compounds (for example, polyfluorinated ethylene). derivatives, etc.), or a combination of two or more thereof. Mixing ratio is 0.001~
About 10%, particularly 0.1 to 5%, is often suitable. The fabric must be antistatic. Woven fabrics using antistatic polyester fibers as wefts have fairly excellent antistatic properties, but if even higher antistatic properties are required, conductive fibers can be used in combination. Conductive fibers include metal fibers, metal-plated fibers, metal compounds (semiconductors, etc.), and other conductive substances (specific resistance).
10 ⁷ Ω・cm or less) on the surface or inside, fibers that have on the surface or inside a conductive layer made of resin mixed with conductive particles or highly conductive components, etc. Examples of the conductive particles include carbon black, metal particles, metal compound particles, and particles having a thin layer of metal or metal compound on their surfaces. Among them, the most suitable is a composite fiber in which a conductive layer containing conductive particles and a protective layer made of a fiber-forming polymer are bonded together. The electrical resistance per 1 cm length of the conductive fiber is preferably 10 ¹¹ Ω or less, most preferably 10 ⁸ Ω or less. The conductive fibers can be combined or twisted with antistatic fibers or non-static fibers, and interlaced with the weft and/or warp, for example, at regular intervals. The antistatic effect of conductive fibers is due to the neutralizing effect of corona discharge, which keeps the charged voltage of the fabric below a certain value (corona discharge starting voltage). On the other hand, antistatic fibers mixed with an antistatic agent have a discharge (attenuation) effect due to conduction and diffusion (grounding) of charges. By using both together, the electrostatic voltage can be kept below a lower fixed value,
Moreover, it can be attenuated quickly. The electrostatic property of fabric is necessary not only to prevent the adsorption of dust and microorganisms due to static electricity, but also to prevent semiconductors from being damaged or fatigued by static electricity in industries that handle semiconductors. For this reason, it is preferable that the electrostatic voltage (absolute value) when the fabric is placed on a wooden table, rubbed sufficiently with a friction cloth made of cotton, wool, or acrylic fiber, and then removed from the table, is 6 KV or less, especially
3KV or less is preferred, and 2KV or less is most preferred.
The method for measuring frictional electrification was developed by the present inventors in Japanese Unexamined Patent Application Publication No. 1986-
Accurate measurement can be achieved by the method disclosed in Japanese Patent No. 48550, particularly by the apparatus disclosed in FIG. 2 or 3 of the same publication. The atmosphere for sample preparation and measurement is 25
℃, 40%RH. (JIS L-1094 (1980) B
(Measuring the frictional charge voltage using a so-called rotary static tester is not preferable because it has large errors and poor reproducibility.) It has been confirmed that the relationship Q=3×10 ¹⁰ E holds between the amount of electricity Q (coulombs/m ² ) of the cloth per unit area and the charged voltage is 8 KV or less. In other words, the charged voltage of 6KV is approximately 1.8μC/
^m2 , 3KV corresponds to a charge density of 0.9μC/ ^m2 , and 2KV corresponds to a charge density of 0.6μC/ ^m2 . Fig. 4 shows a method for measuring dust generation of knitted fabrics. The upper end of the material 21 is fixed to a support rod 22, and a load 23 is attached to the lower end to apply a constant tension. On the other hand, a plurality of friction auxiliaries 25 are attached to the rotary plate 24, and their surfaces are covered with a friction cloth 26. When the rotating plate 24 rotates in the direction of the arrow, the sample 21 is intermittently rubbed by the friction cloth 26, and the generated dust is sucked through the air suction port 27 and transferred to the particle counter 2.
8. 29 is the inlet of clean air from which dust is removed by a high-performance filter;
is the case. If the friction cloth 8 is omitted, dust generation due to friction between the sample and the friction rod can be evaluated. The friction rod may be made of metal, ceramics, resin, etc. depending on the purpose, but it is generally good to have excellent wear resistance, and the shape can be arbitrary, but round rods are common. The friction cloth is also optional, but nylon, polyester, etc., which have excellent abrasion resistance, are preferable. Further, it is also possible to use 26 as a sample and 21 as a friction cloth. In the following example, the sample is 6 cm wide, ultrasonic (melting) cutting is used to prevent dust from being generated on the cut surface, and the sample is folded in half (3 cm wide) and mounted so that the cut part is at the center of the back. The weight shall be 60g. Similarly, the friction rod is made of hard alumina porcelain with a diameter of 8 mm and a length of 6 cm, and the friction cloth is a 40D/10F tricot (knitted fabric) of nylon 6 that does not contain pigments and is ultrasonically cut into a width of 5 cm, with the cut surface in contact with the sample. Install it so that it does not. Disk 11
The rotation speed of is 30 rpm (number of frictions: 180 times/min). Use samples that have been washed with clean water and dried in a clean room. Install the measuring device in a clean room (a clean bench is fine). The air suction rate of the particle counter 15 is 0.5/min. In the following examples, parts, percentages, etc. are expressed as weight ratios unless otherwise specified. Example: PET with a molecular weight of 18,000 was melted, an antistatic agent was continuously mixed in a spinneret with a static mixer, and the temperature was 285℃ and the diameter
Spun from a 0.25mm orifice, cooled, oil-bound, wound at a speed of 150m/min, stretched 3.3 times at 80℃, and subjected to tension heat treatment at 150℃ to produce 150d/48f antistatic yarn.
Got Y1. The antistatic agent is a 92/8 copolymer of polyethylene oxide with a molecular weight of 7,000 and PET and has a molecular weight of 35,000.
and 15% sodium dodecylbenzenesulfonate. The static mixer is the one disclosed in JP-A-47-34166 (Kenix type)
It has 12 elements connected in series, and has the same function as the mixer disclosed by the present inventors in Japanese Patent Publication No. 47-49766. In order to further finely disperse the antistatic agent, a 220-mesh stainless steel filter was installed in front of the spinning orifice. The antistatic agent is dispersed in the form of a large number of fine dots within the cross section of the fiber, and most of the antistatic agent is substantially continuous in the length direction. Let Y2 be the 75d/36f antistatic yarn obtained in the same manner as Y1. Similarly, with normal PET (non-antistatic) drawn yarn
The 150d/48f one is Y3, and the 75d/36f one is Y3.
Let's say Y4. Furthermore, PET (non-antistatic) drawn yarn mixed with 0.2% silicone oil (polymethylphenylsiloxane) during spinning, 150d/48f, is designated as Y5, and 75d/36f is designated as Y6. The shrinkage rate in boiling water is 11% for antistatic yarn.
The non-antistatic yarn is 8%. Y4 is used as the warp thread, however, polyester conductive fiber (Kanebo "Beltron" 20d/
F1 is a fabric obtained by arranging Y4 which is a double yarn of 6f) and using Y1 for the weft. In F1, the weft is thicker than the warp.
Due to its high tension and high shrinkage rate, it sinks and the warp threads float, with a floating height of 51 μm and air permeability of 1.2.
ml/cm ³ /sec, and the charging voltage (maximum value) on the friction fabric wool was -1.8 KV. Make the fabric F2 in the same manner as F1, but use Y6 as the warp and Y1 as the weft. The floating height of F2 is
It is 55 μm. For comparison, a fabric using Y2 for the warp and Y1 for the weft is called F3, and a fabric using Y4 for the warp and Y3 for the weft is called F4. The floating height of F3 and F4 is 20μ each.
m, 23 μm. Table 1 shows the measurement results of air permeability, frictional charging voltage, and frictional dust generation of each fabric. Dust generation is the average number of particles from 28 minutes to 32 minutes after the start of friction, and the particle size (μ
m) Counted by dividing into 5 or more, 2 or more, 1 or more, 0.5 or more, and 0.3 or more. (3 significant figures, rounded off)

【table】

[Table] Effects of the Invention As is clear from Table 1, the product of the present invention has excellent antistatic properties and dustproof properties. This is obtained because an antistatic yarn is used for the sinking yarn and a non-static yarn is used for the floating yarn.

[Brief explanation of drawings]

FIG. 1 is a perspective explanatory view of the dustproof clothing of the present invention, FIG. 2 is a cross-sectional view in the floating direction, and FIG. 3 is a cross-sectional view in the sinking direction. FIG. 4 is an explanatory diagram of a method for measuring dust generation.

Claims (1)

[Scope of Claims] 1 (a) The fabric is made of polyester continuous filament plain woven fabric, (b) The plain woven fabric has a structure in which one of the warp and weft yarns is floating (floating yarn) and the other is sinking (sinking yarn), and (c) the precipitated yarn is an antistatic fiber mixed with an antistatic agent,
The float is a specific antistatic fiber. Dust-proof clothing characterized by: 2. The dust-proof clothing according to claim 1, wherein the average distance (floating height) between the surface of the floating thread and the surface of the sinking thread is 20 to 100 μm. 3 A component occupying 50% or more of the surface area of the non-antistatic fiber contains at least one lubricant selected from the group of paraffin, polyolefin, polyalkylene ether, compound having an alkyl group, organic silicon compound, and organic fluorine compound. Made of polyester that has a reduced coefficient of friction. Dust-proof clothing according to claim 1.