Anti-fray glass cloth

Abstract

To provide a flay prevention glass cloth which has fixed widths of flay prevention processing parts, and has high linearity and excellent productivity.SOLUTION: A flay prevention glass cloth has flay prevention processing parts on both ends in a width direction, wherein both ends in the width direction are cut ends cut along warps, the flay prevention processing part contains a cured product of a resin composition for flay prevention containing 100 pts.mass of a (meth)acrylate monomer having two or more (meth)acryloyl groups in one molecule and a ring structure and 0.25-0.75 pt.mass of a photopolymerization initiator, and has fixed widths from both edge parts along the warps.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fray-resistant glass cloth. [Background technology]

[0002] Currently, with the advancement of high-speed communications such as 5G, there is a strong demand for high-speed communication boards and antenna boards that have low transmission loss even when using high frequencies such as millimeter waves.In addition, in information terminals such as smartphones, there has been a remarkable trend toward high-density packaging and ultra-thinning of wiring boards.

[0003] To lower the dielectric loss tangent of organic resin substrates, such as printed wiring boards for high-speed communications like 5G, inorganic powders or glass cloth, which have a lower dielectric loss tangent than resins, are commonly used. For example, laminates are widely used in which prepregs are laminated and cured under heat and pressure, and the prepregs are impregnated with low-dielectric glass cloth, such as D-glass, NE-glass, or L-glass, with thermoplastic resins, such as fluororesins or polyphenylene ethers, or with thermosetting resins, such as low-dielectric epoxy resins or low-dielectric maleimide resins. However, although glass cloths with improved dielectric properties such as D glass, NE glass, and L glass have been proposed, the dielectric loss tangent of each glass is large, at around 0.002 to 0.005 in the high frequency range of 10 GHz or higher. When high frequencies such as millimeter waves are used for communication, the transmission loss is large and accurate information cannot be transmitted. It is known that the signal transmission loss is improved as the dielectric constant (ε) and dielectric loss tangent (tanδ) of a material decrease, as indicated by the Edward A. Wolff equation: transmission loss ∝√ε×tanδ.

[0004] As an even lower dielectric glass cloth, silica glass cloth containing 95% or more by mass of SiO2 is generally known to have very good dielectric properties. For example, Patent Document 1 reports silica glass cloth with a dielectric loss tangent of 0.0020 or less at 10 GHz, and the use of such glass cloth in substrates and antenna substrates for future high-speed communications such as 5G can reduce transmission loss.

[0005] On the other hand, glass cloth is woven using a shuttleless loom such as an air jet loom. In a shuttleless loom, the weft yarn inserted into the glass cloth is cut after each insertion in accordance with the woven width of the glass cloth. Therefore, the ends (selvages) of the glass cloth are prevented from fraying with selvage yarns (tassel selvage treatment) to prevent defects in the weave. When such glass cloth having fringes is used in a process of impregnating it with varnish such as a low dielectric resin to produce prepreg, resin pellets are generated at the fringe portions, and the resin pellets fall onto the product at the roller section, significantly impairing the quality.

[0006] Furthermore, when cutting glass cloth to any desired dimensions, if the cutting is performed without any anti-fraying treatment, the warp threads will easily fray at the cut portion, and when such glass cloth is impregnated with varnish, problems such as the frayed warp threads winding around a roll will occur.

[0007] Therefore, Patent Documents 2 to 4 propose anti-fraying treatment agents using epoxy resins, ester resins, polyether polymers, and the like to prevent fraying. However, all of these methods require a step of drying the anti-fraying agent by heating, and such anti-fraying treatments require a long time for drying and curing, resulting in poor productivity. Furthermore, Patent Document 5 proposes a method for preventing fraying in which ultraviolet rays are irradiated onto the edge portions of glass cloth to which a resin solution has been applied to harden the resin. However, since the ultraviolet-curable resin is diluted with water or an organic solvent, a drying step is required to remove the moisture, which results in poor productivity.

[0008] When glass cloth is used to manufacture prepreg, the fray prevention treatment portion is cut off and unused when the prepreg is processed into a printed wiring board after formation, so the fray prevention treatment portion needs to be highly linear and have a constant width as narrow as possible while preventing fraying. However, Patent Documents 2, 3, 5 and 6 describe the width of the fray prevention processed portion, but do not describe the linearity. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent Publication No. 2021-063320 [Patent Document 2] Japanese Patent Application Publication No. 8-13343 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-81671 [Patent Document 4] Patent No. 6604893 [Patent Document 5] Japanese Patent Application Laid-Open No. 2001-181982 [Patent Document 6] Japanese Patent Application Publication No. 8-260340 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made to solve the above problems, and has as its object to provide a fray-preventing glass cloth in which the fray-preventing treated portion has a uniform width, high linearity, and excellent productivity. [Means for solving the problem]

[0011] As a result of extensive research to achieve the above object, the inventors have found that a fray-preventing glass cloth, which is produced by applying a solventless fray-preventing resin composition to both widthwise ends of a raw glass cloth in a predetermined application width, curing the composition with ultraviolet light, cutting the cured resin-treated portion along the warp at predetermined positions, and removing the portions from both widthwise edges of the raw glass cloth up to the predetermined positions of the resin-treated portion, has a fray-preventing treated portion of a uniform width, high linearity, and excellent processability and productivity, which has led to the present invention.

[0012] Therefore, the present invention provides 1. A fray-preventing glass cloth having fray-preventing treatment sections at both widthwise ends, the widthwise ends are cut ends cut along the warp yarns, a fray-preventing glass cloth, wherein the fray-preventing treated portion comprises a cured product of a fray-preventing resin composition containing 100 parts by mass of a (meth)acrylate monomer having two or more (meth)acryloyl groups and a ring structure in one molecule and 0.25 to 0.75 parts by mass of a photopolymerization initiator, and the fray-preventing glass cloth has a constant width along the warp yarns from both edges; 2. The fray-preventing glass cloth according to 1, wherein the width of the fray-preventing treated portion is 5 mm or less from each edge, and the variation in width is ±0.5 mm or less. 3. The fray-resistant glass cloth according to 1 or 2, wherein the SiO2 content of the glass yarn constituting the glass cloth is 95% by mass or more. 4. A weaving process in which raw glass cloth is woven using glass yarns as warp and weft threads; a coating step of coating the obtained raw glass cloth with a solvent-free fray-preventing resin composition, which contains 100 parts by mass of a (meth)acrylate monomer having two or more (meth)acryloyl groups and a ring structure in one molecule and 0.25 to 0.75 parts by mass of a photopolymerization initiator, along the warp yarns from both widthwise edges of the raw glass cloth, with a fixed coating width; an ultraviolet irradiation step of irradiating the applied resin composition with ultraviolet light to cure the resin composition and form a resin-treated portion; a cutting step of cutting the resin-treated portion along the warp yarns at predetermined positions in the resin-treated portion to remove portions of the raw glass cloth from both widthwise edges up to the predetermined positions in the resin-treated portion; A method for producing fray-resistant glass cloth, which does not include a drying step of drying a resin composition applied to a raw glass cloth. to provide. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a fray-preventing glass cloth in which the fray-preventing treated portion has a uniform width, high linearity, and excellent processability and productivity. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be described in detail below. The fray-preventing glass cloth of the present invention is a fray-preventing glass cloth obtained by applying a solvent-free fray-preventing resin composition to both widthwise ends of a raw glass cloth in a predetermined application width, curing the composition with ultraviolet light, cutting the cured resin-treated portion along the warp at predetermined positions, and removing the portions from both widthwise edges of the raw glass cloth to the predetermined positions of the resin-treated portion to form fray-preventing treated portions. In this specification, a thin thread-like single fiber obtained by stretching glass is defined as a glass filament, a bundle of glass filaments is defined as a glass strand, and a twisted glass strand is defined as a glass yarn.

[0015] [Raw glass cloth] (1) Glass composition The raw glass cloth used in the present invention is woven using glass yarns consisting of a plurality of glass filaments as warp and weft. In terms of dielectric properties, the glass filaments used in the present invention are preferably made of quartz glass with an SiO2 content of 95% by mass or more, and more preferably 99.9% by mass or more. Such quartz glass may be either synthetic quartz glass or fused quartz glass. Components other than SiO2 include Al2O3, CaO, MgO, BO3, Na2O, etc. For the glass cloth used in laminates such as printed wiring boards, E glass (alkali-free glass) having an SiO2 content lower than the above range is usually used.

[0016] (2) Filament Glass filaments are thin, thread-like single fibers obtained by stretching glass. The average diameter of the filaments constituting the glass yarn of the present invention is not particularly limited, but is preferably, for example, 3 to 20 μm, more preferably 3.5 to 14 μm.

[0017] (3) Strand The strand is a bundle of glass filaments. In the present invention, the strand is preferably formed by bundling 30 to 400 of the above filaments, more preferably 35 to 300.

[0018] (4) Glass yarn Glass yarn is a twisted glass strand. The twist number of the glass yarn of the present invention is, for example, preferably 4 to 200 turns / m, more preferably 5 to 100 turns / m, and even more preferably 10 to 50 turns / m.

[0019] (5) Weaving structure, weaving density The weave structure, weave density, etc. of the raw glass cloth used in the present invention are not particularly limited, but examples of the weave structure include plain weave, satin weave, sash weave, twill weave, etc. The weave density is preferably, for example, 10 to 130 threads / 25 mm.

[0020] [Manufacturing method of raw glass cloth] The method for producing the raw glass cloth of the present invention is not particularly limited, and it can be produced by a known method, for example, a method including the following steps. (1) Weaving process in which raw glass cloth is woven using glass yarns as warp and weft. (2) A fiber-opening process for opening the glass yarn of the raw glass cloth, if necessary. (3) If necessary, a desizing step for removing a sizing agent when a sizing agent is used to bundle the glass strands. (4) A surface treatment step of treating the raw glass cloth with a surface treatment agent, if necessary.

[0021] (1) Weaving process The weaving process is a process in which glass yarn is woven to obtain raw glass cloth. The weaving method is not particularly limited, and can be carried out by appropriately selecting from conventionally known looms, for example, by using a rapier loom, a shuttle loom, or an air jet loom.

[0022] (2) Opening process The opening step is a step of opening the glass yarns of the raw glass cloth as needed. The raw glass cloth obtained in the weaving step can be used as it is, but if necessary, it can be subjected to an opening treatment in order to improve the impregnation property with a resin solution or the like and the surface smoothness when the fray-resistant glass cloth of the present invention is used for a prepreg, etc. The opening treatment method is not particularly limited, and examples thereof include methods using ultrasonic waves, high-pressure water, a diffusion spray, a gas-liquid mixed mist, etc.

[0023] (3) Desizing process The desizing step is a step of removing the sizing agent used in producing the glass strands, if necessary. The desizing method is not particularly limited, but examples thereof include heating, washing with water, etching, and the like.

[0024] (4) Surface treatment process The surface treatment step is a step in which the raw glass cloth is treated with a surface treatment agent, if necessary. The raw glass cloth obtained in the weaving step can be used as it is, but if necessary, it can be treated with a surface treatment agent such as a silane coupling agent in order to improve the impregnation properties of a resin solution or the like when the fray-resistant glass cloth of the present invention is used in a prepreg or the like, or to improve the adhesiveness at the interface between the low dielectric resin and the fray-resistant glass cloth.

[0025] The surface treatment agent is not particularly limited, but is preferably one which provides a stable treated surface and has an unsaturated group-containing functional group capable of chemically bonding with an organic resin, such as a silane coupling agent having a functional group such as a vinyl group, a styryl group, or a (meth)acryloyl group. Note that the (meth)acryloyl group means an acryloyl group or a methacryloyl group. Specific examples of the silane coupling agent include γ-(meth)acryloxypropyldimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyldiethoxysilane, γ-(meth)acryloxypropyltriethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane; and p-styryltrimethoxysilane. These may be selected depending on the raw glass cloth to be surface treated and the resin to be used for the prepreg, and may be used alone or in combination of two or more. The amount of the surface treatment agent is not particularly limited, but is preferably 0.05 to 1.0 part by mass per 100 parts by mass of the raw glass cloth.

[0026] [Anti-fray glass cloth] (1) Raw glass cloth As the raw glass cloth, those mentioned above can be used.

[0027] (2) Anti-fraying resin composition (anti-fraying treatment agent) The anti-fraying resin composition used in the present invention contains a (meth)acrylate monomer having two or more (meth)acryloyl groups and a ring structure per molecule, and a photopolymerization initiator. Because quartz glass cloth made from quartz glass yarn is brittle, a non-heating, ultraviolet-curable anti-fraying resin composition (anti-fraying agent) is preferred.

[0028] (2-1) (Meth)acrylate Monomer Examples of (meth)acrylate monomers having two or more, preferably 2 to 8, and more preferably 2 to 6 (meth)acryloyl groups and ring structures per molecule include (meth)acrylate monomers that contain two or more (meth)acryloyl groups and an aliphatic cyclic skeleton, an aromatic ring skeleton, or a heterocyclic structure per molecule, and that may contain an ether bond or an ester bond. Specific examples include dicyclopentanyl di(meth)acrylate, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloxytetraethoxyphenyl)propane, 2-(1,2-cyclohexacarboximide)ethyl acrylate, and tricyclodecane dimethanol di(meth)acrylate. These may be used alone or in combination of two or more. Among these, tricyclodecane dimethanol di(meth)acrylate is preferred because it has a large solvent resistance effect.

[0029] (2-2) Photopolymerization initiator The photopolymerization initiator used in the present invention is not particularly limited as long as it generates radicals upon irradiation with ultraviolet light, an electron beam, or the like and the radicals trigger a polymerization reaction, and general-purpose photopolymerization initiators such as benzyl ketal-based, acetophenone-based, and phosphine oxide-based compounds can be used. By arbitrarily selecting the light absorption wavelength of the photopolymerization initiator, it is possible to impart curability over a wide wavelength range from the ultraviolet region to the visible light region.

[0030] Specific examples of the photopolymerization initiator include benzyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one; α-hydroxyacetophenone compounds such as 1-hydroxy-cyclohexyl-phenyl-ketone and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one; α-aminoacetophenone compounds such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one; and acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like. These may be used alone or in combination of two or more. Among these, α-hydroxyacetophenone compounds that are resistant to yellowing and acylphosphine oxide compounds that have excellent internal curing properties are preferred. These are commercially available products, such as Omnirad 819 for α-hydroxyacetophenone compounds and Omnirad TPOH for phosphine oxide compounds (both trade names: manufactured by iGM Resins).

[0031] The amount of the photopolymerization initiator to be added is 0.25 to 0.75 parts by mass, preferably 0.3 to 0.65 parts by mass, and more preferably 0.3 to 0.5 parts by mass, relative to 100 parts by mass of the (meth)acrylate monomer. 5 If the amount exceeds 0.2 parts by mass, the photopolymerization initiator will remain and the anti-fraying treatment agent will turn yellow. 5 If the amount is less than 1 part by mass, curing will be insufficient.

[0032] (2-3) Other ingredients The anti-fraying resin composition (anti-fraying treatment agent) used in the present invention may further contain oligomers such as urethane (meth)acrylate, antistatic agents, etc., as needed, within the range that does not inhibit photocurability.

[0033] [Method for manufacturing fray-resistant glass cloth] The method for producing the fray-resistant glass cloth of the present invention includes, for example, a method comprising the following steps. (11) A coating step of coating the resin composition (fray prevention agent) along the warp yarns from both widthwise edges of the raw glass cloth described above with a constant coating width. (12) An ultraviolet irradiation step of irradiating the applied resin composition with ultraviolet light to harden the resin composition and form a resin-treated portion. (13) a cutting step in which the resin-treated portion is cut along the warp at predetermined positions to remove the portions of the raw glass cloth from both widthwise edges up to the predetermined positions of the resin-treated portion.

[0034] (11) Coating process The coating step is a step of coating the anti-fraying resin composition along the warp yarns from both widthwise edge portions of the raw glass cloth with a constant coating width. The method for applying the resin composition is not particularly limited and can be appropriately selected from conventionally known methods, such as roller coating, die coating, spray coating, curtain coating, etc. From the viewpoint of reducing variation in the coating width, roller coating and die coating are preferred as the application method. The coating width is, for example, preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less from each of the widthwise edges of the raw glass cloth. The coating width variation is preferably ±1.0 mm, more preferably ±0.5 mm, and even more preferably ±0.3 mm.

[0035] (12) Ultraviolet irradiation process The ultraviolet irradiation step is a step of irradiating the applied resin composition with ultraviolet light to cure the resin composition and form a resin-treated portion. The method of ultraviolet irradiation is not particularly limited, but examples include irradiation using a mercury lamp, a metal halide lamp, an ultraviolet light-emitting diode (ultraviolet LED), etc. Ultraviolet LED is preferred because of its high energy efficiency and long life. The cumulative light intensity during UV curing is 500mJ / cm 2 More than 500mJ / cm is preferable. 2If the temperature is less than this, poor curing such as tackiness may occur.

[0036] (13) Cutting process The cutting step is a step of cutting the raw glass cloth along the warp at predetermined positions in the resin treatment section to remove portions from both widthwise edges of the raw glass cloth up to the predetermined positions in the resin treatment section. The method for cutting the resin-treated portion is not particularly limited, but examples thereof include cutting using a slit blade such as a razor blade, rotary razor blade, score blade, shear blade, or circular blade. The material of the slit blade is not particularly limited, but examples thereof include carbon steel, high-speed steel, cemented carbide, and ultrafine particle cemented carbide. The slit blade may or may not be surface-treated. When a surface-treated blade is used, the surface treatment method is not particularly limited, but examples thereof include surface treatment methods such as mirror finishing, fluorine coating, and silicone coating.

[0037] The cutting position is not particularly limited as long as it ensures that the resulting fray-preventing treated portion has a consistent width and, if there is a defect in the weave at the end of the raw glass cloth, the defective portion can be removed. For example, it is preferably at a position not more than 15 mm, more preferably not more than 12.5 mm, and even more preferably not more than 10 mm from each of the widthwise edges of the raw glass cloth. This can be determined depending on the application width of the resin-treated portion and the width of the fray-preventing treated portion after cutting. Furthermore, from the viewpoints of work efficiency and finish stability, the cutting position is preferably the center of the resin-treated portion in width, but is not particularly limited. This allows for the formation of fray-preventing treated portions with a width of preferably not more than 10 mm, more preferably not more than 7.5 mm, and even more preferably not more than 5 mm from each of the edges (cut portions) of the glass cloth after cutting along the warp. The fray-preventing treated portion of the fray-preventing glass cloth of the present invention has a uniform width, is non-meandering, and has high linearity. Furthermore, since the resin composition for the fray-preventing treatment does not contain water or an organic solvent, a drying step of the resin composition is not required, and the processability and productivity are excellent. [Example]

[0038] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0039] [1] Manufacturing of anti-fray glass cloth [Example 1] A light-shielding bottle was charged with 100 parts by mass of the bifunctional acrylate tricyclodecane dimethanol diacrylate as the resin monomer for the anti-fraying treatment agent, and 0.5 parts by mass of Omnirad819 (an α-hydroxyacetophenone compound manufactured by IGM) as a photopolymerization initiator, and the mixture was stirred for at least 5 minutes using a stirring defoamer until homogenous, yielding an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth with a weave density of 53 x 54 / 25 mm, which was woven using a quartz glass yarn with an SiO2 content of 99.9 mass% or more and a twist rate of 24 turns / m, consisting of a bundle of 200 quartz glass filaments with an average filament diameter of 5.3 μm. The cloth was then roller coated to a coating width of 10 mm from each of the widthwise edges, and the cloth was then coated with a 365 nm ultraviolet LED at an integrated light dose of 500 mJ / cm. 2 It was hardened with. Using a circular blade made of high-speed steel SKH51 with a cutting edge angle of 5°, the glass cloth was cut along the warp threads at a position 5 mm from the center of the width of the anti-fraying treatment area (5 mm from the edge) to remove both ends, producing anti-fraying treated glass cloth.

[0040] [Example 2] A light-shielding bottle was charged with 60 parts by mass of the bifunctional acrylate tricyclodecane dimethanol diacrylate as the resin monomer for the anti-fraying treatment agent, 40 parts by mass of EBECRYL220 (trade name: manufactured by Daicel-Allnex Corporation) as a hexafunctional aromatic urethane acrylate oligomer, and 0.5 parts by mass of Omnirad819 (manufactured by IGM, an α-hydroxyacetophenone-based compound) as a photopolymerization initiator, and the mixture was stirred for at least 5 minutes using a stirring defoamer until uniform, yielding an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth in the same manner as in Example 1, cured with ultraviolet light, and cut to prepare anti-fraying treated glass cloth.

[0041] [Comparative Example 1] A light-shielding bottle was charged with 100 parts by mass of the bifunctional acrylate tricyclodecane dimethanol diacrylate as the resin monomer for the anti-fraying treatment agent, and 1.0 part by mass of Omnirad819 (an α-hydroxyacetophenone compound manufactured by IGM) as a photopolymerization initiator, and the mixture was stirred for at least 5 minutes using a stirring defoamer until homogenous, yielding an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth in the same manner as in Example 1, cured with ultraviolet light, and cut to prepare anti-fraying treated glass cloth.

[0042] Comparative Example 2 100 parts by mass of the bifunctional acrylate tricyclodecane dimethanol diacrylate as the resin monomer for the anti-fraying treatment agent and 0.2 parts by mass of Omnirad819 (an α-hydroxyacetophenone compound manufactured by IGM) as a photopolymerization initiator were placed in a light-shielding bottle and stirred for at least 5 minutes using a stirring defoamer until the mixture was homogenous, yielding an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth in the same manner as in Example 1, cured with ultraviolet light, and cut to prepare anti-fraying treated glass cloth.

[0043] Comparative Example 3 100 parts by mass of 2-ethylhexyl acrylate, a monofunctional acrylate, was placed in a light-shielding bottle as the resin monomer for the anti-fraying treatment agent, and 0.5 parts by mass of Omnirad819 (an α-hydroxyacetophenone compound manufactured by IGM) was placed in a light-shielding bottle, and the mixture was stirred for at least 5 minutes using a stirring defoamer until homogenous, yielding an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth in the same manner as in Example 1, cured with ultraviolet light, and cut to prepare anti-fraying treated glass cloth.

[0044] Comparative Example 4 A light-shielding bottle was charged with 60 parts by mass of 2-ethylhexyl acrylate, a monofunctional acrylate, as the resin monomer for the anti-fraying treatment agent, 40 parts by mass of EBECRYL220 (trade name: manufactured by Daicel-Allnex Corporation) as a hexafunctional aromatic urethane acrylate oligomer, and 0.5 parts by mass of Omnirad819 (manufactured by IGM, an α-hydroxyacetophenone-based compound) as a photopolymerization initiator, and the mixture was stirred for at least 5 minutes using a stirring defoamer until homogenous, yielding an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth in the same manner as in Example 1, cured with ultraviolet light, and cut to prepare anti-fraying treated glass cloth.

[0045] Comparative Example 5 90 g of water was placed in a glass beaker, and 10 g of Vinyblanc 1008 (trade name: vinyl acetate copolymer, manufactured by Nissin Chemical Industry Co., Ltd.) was added thereto and stirred until completely mixed to obtain an anti-fraying treatment agent. The obtained anti-fraying agent was applied to a quartz glass cloth, cured by heating, and cut in the same manner as in Example 1 to prepare anti-fraying treated glass cloth.

[0046] Comparative Example 6 A quartz glass cloth with a weave density of 53 x 54 / 25 mm was woven using a quartz glass yarn with a twist rate of 24 turns / m, which was made by bundling 200 quartz glass filaments with an SiO2 content of 99.9 mass% or more and an average filament diameter of 5.3 μm. The cloth was cut using a circular blade made of high-speed steel SKH51 with a cutting edge angle of 5°.

[0047] [2] Characterization The fray-resistant glass cloths obtained in the above Examples and Comparative Examples were evaluated according to the following methods. The results are shown in Table 1. <Width variation> The width of the fray-preventing glass cloth from the cut portion of the fray-preventing treatment was measured at 10 points every 5 cm along the length of the cloth, and the average was calculated to calculate the variation. <Appearance> The fray-preventing treated portion of the fray-preventing glass cloth was visually inspected for air bubbles and foreign matter. When no air bubbles or foreign matter were found, the result was rated as "good," and when they were found, the result was rated as "poor." <Fraying when cut> Immediately after ultraviolet irradiation, the cut surface of the fray-preventing treated portion of the fray-preventing glass cloth was visually inspected, and if no fraying or misalignment was observed, it was rated as good, and if any was observed, it was rated as x. <Fraying due to friction> Immediately after ultraviolet irradiation, the fray-preventing treated portion of the fray-preventing glass cloth was rubbed 10 times at 1.17 MPa and visually inspected. If no fraying or misalignment was observed, it was rated as good, and if any was observed, it was rated as x. <Tack-free> The degree of stickiness of the fray prevention treated part of the fray prevention glass cloth immediately after ultraviolet irradiation was confirmed by touching with the fingers in accordance with 10. Tack-free test of JIS K6249:2003, and if there was no stickiness it was rated as good, and if there was stickiness it was rated as x. <Solvent resistance> Immediately after UV irradiation, 10 mL of toluene was dropped onto the fray prevention treated part of the fray prevention glass cloth, and the occurrence of warping was checked 1 minute after the drop. If no warping occurred, it was rated as good, and if there was warping, it was rated as x.

[0048] [Table 1]

[0049] The fray-resistant glass cloths obtained in Examples 1 and 2 have excellent processability due to the short curing time and excellent resistance to the organic solvents contained in the varnish used in prepreg production, as the resin is cured by ultraviolet irradiation.

Claims

1. A fray-preventing glass cloth having fray-preventing treatment portions at both widthwise ends, the widthwise ends are cut ends cut along the warp yarns, the fray prevention treated portion comprises a cured product of a fray prevention resin composition containing 100 parts by mass of a (meth)acrylate monomer having two or more (meth)acryloyl groups and a ring structure in one molecule and 0.25 to 0.75 parts by mass of a photopolymerization initiator, and has a constant width along the warp yarns from both edges, The fray-preventing glass cloth has a width of 5 mm or less from each edge of the fray-preventing treated portion, and the width variation is ±0.5 mm or less.

2. SiO of glass yarns constituting glass cloth 2 2. The fray-preventing glass cloth according to claim 1, wherein the content is 95% by mass or more.

3. a weaving process for weaving raw glass cloth using glass yarns as warp and weft; a coating step of coating the obtained raw glass cloth with a solvent-free fray-preventing resin composition, the composition comprising 100 parts by mass of a (meth)acrylate monomer having two or more (meth)acryloyl groups and a ring structure in one molecule and 0.25 to 0.75 parts by mass of a photopolymerization initiator, along the warp yarns from both widthwise edges of the raw glass cloth, with a constant coating width; an ultraviolet irradiation step of irradiating the applied resin composition with ultraviolet light to cure the resin composition and form a resin-treated portion; a cutting step of cutting the resin-treated portion along the warp yarns at predetermined positions in the resin-treated portion to remove portions of the raw glass cloth from both widthwise edges up to the predetermined positions in the resin-treated portion; The method for producing fray-resistant glass cloth includes the steps of:

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