KR20220168438A - Sizing composition and glass fiber using the same - Google Patents

Abstract

The present invention relates to a sizing composition for glass fibers, and the glass fibers manufactured by using the same. The sizing composition for glass fibers of the present invention includes: a film forming agent including a polyurethane resin and a novolak-type epoxy resin; and a silane coupling agent including an amino silane and an epoxy silane. In addition, the present invention provides glass fibers which are coated with the aforementioned sizing composition, and which improve the mechanical strength and hydrolysis resistance of thermoplastic composite materials.

Description

Sizing composition and glass fiber using the same {Sizing composition and glass fiber using the same}

The present invention relates to a sizing composition for glass fibers and glass fibers manufactured using the same.

Due to its characteristics such as excellent strength, insulation, incombustibility, dimensional stability, and chemical resistance, glass fiber is widely used as a strength reinforcing material for building materials and polymer materials using electrical insulation properties. After melting various oxides that form glass, glass filaments in the form of thin threads are pulled out through a bushing, coated with a sizing composition, and then plied to form a strand. , processed into various forms and applied to various fields.

The sizing composition is coated on the surface of the glass fiber and serves to increase the adhesion between the glass fiber and the plastic interface during compounding. The sizing composition is composed of a film forming agent, a coupling agent, and other additives, and various researches and developments have been conducted on sizing compositions including a film forming agent and a coupling agent of various compositions in order to impart excellent physical properties to glass fibers. For example, Korean Patent Publication No. 10-2018-0067592 discloses a coating composition for reinforcing fibers using a film forming agent including at least one of polyvinylpyrrolidone, polyvinyl acetate and polyurethane.

However, conventional sizing compositions have limitations in imparting sufficient physical properties to glass fibers, and in particular, limitations in imparting sufficient physical properties to glass fibers for reinforcing polyester resins such as polyethylene terephthalate and polybutylene terephthalate. Polyester resin is widely used as a major component throughout the industry due to its excellent mechanical, thermal, and electrical properties. As a result, there is a disadvantage in that the flow of the resin is increased and the mechanical properties are lowered. In particular, in the glass fiber reinforced molded composite, the interface between the glass fiber and the polyester matrix acts as a major passage for moisture incorporation, which can accelerate the degradation of the physical properties of the polyester composite, and for this reason, use in high temperature and high humidity environments may be limited. can

The present invention provides a sizing composition for coating glass fibers.

In addition, the present invention provides glass fibers coated with the aforementioned sizing composition, which serves to improve mechanical strength and hydrolysis resistance of thermoplastic composites.

The present invention provides a sizing composition comprising a film former comprising a polyurethane resin and a novolac-type epoxy resin and a silane coupling agent comprising amino silane and epoxy silane.

In addition, the present invention provides a glass fiber coated with the above-described sizing composition and a thermoplastic polymer composite material including the same.

Thermoplastic polymer composites (eg, glass fiber-reinforced polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, etc.) comprising glass fibers coated with the sizing composition according to the present invention exhibit excellent mechanical strength and hydrolysis resistance. .

Hereinafter, the present invention will be described in detail. However, it is not limited only by the following contents, and each component may be variously modified or selectively mixed as needed. Therefore, it should be understood to include all modifications, equivalents or substitutes included in the spirit and scope of the present invention.

As used herein, “weight average molecular weight” and “number average molecular weight” are measured by a conventional method known in the art, and can be measured, for example, by a gel permeation chromatograph (GPC) method. In addition, "glass transition temperature" is measured by a conventional method known in the art, and can be measured, for example, by differential scanning calorimetry (DSC).

<Sizing composition>

The sizing composition according to the present invention includes a film former and a silane coupling agent.

film former

The sizing composition according to the present invention includes a polyurethane resin and an epoxy resin as film formers.

The polyurethane resin serves to impart mechanical strength and binding between the glass fiber filaments either alone or in combination with silane. The polyurethane resin is prepared by the reaction of a polyol and an isocyanate.

As the polyol, a common polyol used in synthesizing a urethane resin may be used without particular limitation. Non-limiting examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, and acrylic polyol, such as polyethylene adipate polyol, polybutylene adipate polyol, polyethylenebutylene adipate polyol, and polycapro lactone polyol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyether polyester polyol. The above components may be used alone or in combination of two or more.

As the isocyanate, a common isocyanate compound used in synthesizing a urethane resin may be used without limitation. For example, methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), metaxylene diisocyanate (MXDI), tetramethylxylene diisocyanate (TMXDI), diisocyanate made alicyclic by adding hydrogen to the benzene ring of MDI (H12 MDI), diisocyanate made alicyclic by adding hydrogen to the benzene ring of xylene diisocyanate (XDI) (hydrogenated XDI) etc. The above components may be used alone or in combination of two or more.

The polyurethane resin may be an epoxy-modified polyurethane resin. The epoxy-modified polyurethane resin may be prepared by a reaction between a polyurethane resin and an epoxy, and epoxy-modified polyurethane is synthesized by combining -OH groups in epoxy and -NCO groups in polyurethane. In the case of using the epoxy-modified polyurethane resin, the polyurethane component in the resin maintains the glass fibers, and at the same time, the strength properties and hydrolysis resistance can be improved due to the epoxy component that serves as a crosslink with the matrix resin. .

The polyurethane resin is used in a form dispersed in water, and may include an ionic or nonionic emulsifier for dispersion stability. The pH of the water-dispersed polyurethane resin may be 6.0 to 10.0, for example 6.5 to 9.0. When the pH is less than 6, dispersion stability may decrease when the polyurethane resin is dispersed in water, and when the pH exceeds 10, stability of the sizing solution including the silane coupling agent may decrease due to silane condensation.

The polyurethane resin may have a number average molecular weight of 20,000 to 60,000 g/mol, for example, 35,000 to 45,000 g/mol. In addition, the polyurethane resin may have a weight average molecular weight of 65,000 to 105,000 g/mol, for example, 85,000 to 95,000 g/mol. If the molecular weight of the polyurethane resin is less than the above range, mechanical properties may be deteriorated during film formation of the urethane resin itself, and physical properties may be deteriorated. may be lowered

The polyurethane resin may have a glass transition temperature of -60 to -20 °C, for example -50 to -30 °C. When the glass transition temperature of the polyurethane resin is less than the above range, polyurethane is softened, so impact strength and elongation are improved, but tensile strength and flexural strength may be reduced. On the other hand, when the glass transition temperature exceeds the above-mentioned range, since the softness of the polyurethane is deteriorated, the tensile strength and flexural strength are improved, but the impact strength and elongation are reduced, and the collecting performance of the glass fibers may be deteriorated.

Since the novolak-type epoxy resin contains a large number of functional groups in the molecule, the crosslinking density is increased by increasing the number of functional groups in the bundling agent, and as a result, excellent hydrolysis resistance can be secured.

As the novolak-type epoxy resin, O-cresol novolak epoxy resin, BPA-novolac epoxy resin, novolak epoxy resin, and mixtures thereof may be used.

The epoxy equivalent of the novolac-type epoxy resin may be 150 to 300 g/eq, for example 185 to 255 g/eq. When the epoxy equivalent of the novolac-type epoxy resin is less than the above range, the molecular weight is low, and initial strength may be reduced. Degradability may be reduced.

The mixing ratio (weight ratio, based on solid content) of the urethane resin and the novolac-type epoxy resin may be 1:3 to 8, for example, 1:4 to 7. If the mixing ratio of the novolac-type epoxy resin to the urethane resin is less than the above range, the adhesive force between the glass fiber and plastic interface may be insufficient, and mechanical properties may be relatively poor. Poor convergence between glass fiber filaments reduces workability, and when extruded, glass fiber input variation may reduce physical properties and data reliability.

The film forming agent may be included in an amount of 70 to 95% by weight, for example, 80 to 95% by weight based on the total solid content of the sizing composition. If the content of the film forming agent is less than the above range, convergence between the glass fiber filaments may be poor, and if it exceeds the above range, the amount of the coupling agent is insufficient, resulting in a couple between the glass fiber and the film former or the glass fiber and the plastic. The ring effect is not sufficient, and as a result, the mechanical strength may be inferior.

Silane coupling agent

The silane coupling agent serves to provide adhesion between inorganic glass and organic film formers or thermoplastic engineering plastics. The silane coupling agent forms a siloxane bond through a dehydration condensation reaction with a silanol group on the surface of the glass fiber in the form of silanol by hydrolysis of the alkoxy group in water. At this time, the silane coupling agent is oriented or bonded to the surface of the glass fiber, and serves as a coupling agent that protects the glass surface and imparts interfacial adhesion between the film forming agent and the glass.

The sizing composition according to the present invention includes amino silane and epoxy silane as silane coupling agents. The amino silane supplements the bundling of the glass fibers, and the epoxy silane having the same functional group as the epoxy film forming agent improves hydrolysis resistance.

Examples of the amino silane include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, and γ-aminopropylmethyldimethoxy. Silane etc. can be used, These can be used individually or in mixture of 2 or more types.

Examples of the epoxy silane include vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-acryloxypropyltrimethoxysilane. , γ-acryloxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, dimethyldimethoxysilane, vinylmethyldimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxy Silane, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, and the like can be used, and these can be used alone or in combination of two or more.

The mixing ratio (weight ratio, solid content basis) of the amino silane and the epoxy silane may be 1:1 to 1.8, for example, 1:1 to 1.5. When the mixing ratio of epoxy silane to amino silane is less than the above range, the number of epoxy functional groups is small, and thus hydrolysis resistance may be deteriorated.

The silane coupling agent may be included in an amount of 5 to 30% by weight, for example, 5 to 20% by weight based on the total solid content of the sizing composition. If the content of the silane coupling agent is less than the above range, the coupling effect between the glass fiber and the film forming agent or between the glass fiber and the plastic may be insufficient, resulting in poor mechanical strength. Fiber dispersion may be poor, or glass fiber bundle may be poor due to an insufficient amount of the film forming agent.

additive

The sizing composition of the present invention may further include additives commonly used in the art within a range that does not impair the inherent properties of the sizing composition. Non-limiting examples of the additives usable in the present invention include a coagulant aid resin for improving the cohesiveness of glass fibers, a lubricant for imparting surface lubricity, a buffer agent for adjusting pH, and a color stabilizer. These may be used alone or in combination of two or more.

The additives may be added within a known content range in the art, for example, 0.01 to 10% by weight, for example, 0.1 to 1% by weight, based on the total solid content of the sizing composition.

<Glass Fiber>

The present invention provides glass fibers surface-treated with the aforementioned sizing composition.

The glass fiber substrate usable in the present invention is not particularly limited as long as it is known in the art. Examples include E-glass, D-glass, S-glass, NE-glass, T-glass, and Q-glass, but are not limited thereto.

The fiber diameter of the glass fiber may be 5 to 20 μm, for example, 8 to 15 μm. If the fiber diameter is less than the above range, excessive fiber damage may occur during the extrusion and injection processes, and the strength of the glass fiber-reinforced thermoplastic engineering plastic molded article may be inferior, and the breakage rate increases during the glass fiber manufacturing process, resulting in a decrease in productivity. When the above range is exceeded, the strength reinforcing effect of the glass fiber may be reduced due to the decrease in the surface area of the glass fiber.

The fiber length of the glass fiber may be 1 to 20 mm, for example, 2 to 10 mm. If the fiber length is less than the above range, the strength reinforcing effect of the final glass fiber reinforced thermoplastic composite material may be reduced due to fiber breakage occurring during the extrusion and injection processes, and if the fiber length exceeds the above range, the input and The uniform dispersion may be poor, and the strength reinforcing effect may be lowered.

As a method of applying the sizing composition, a dipping method, a roll coating method, a die coating method, a gravure coating method, a spray coating method, a flow coating method, and the like may be used, but are not limited thereto. In one example, the sizing composition can be applied to a glass fiber substrate using an immersion method, in which case the immersion time is several milliseconds to several seconds.

The application amount of the sizing composition is not particularly limited, but may be 0.1 to 1.5 parts by weight, for example, 0.3 to 1.0 parts by weight, based on 100 parts by weight of the solid content of the glass fibers. If the application amount of the sizing composition is less than the above range, the cohesion of the glass fiber bundle may deteriorate, resulting in deterioration of workability in the extrusion process. If the amount exceeds the above range, product appearance and It can cause quality problems.

Glass fibers coated with the sizing composition are usually in the form of filaments, and several strands (eg, 4,000) are plied to form strands. These strands can be processed into various shapes through various processing processes and applied to various fields. For example, the strands may be processed by chopping, cut into a predetermined length (eg, 2 to 5 mm), and dried to obtain a form of chopped strands. The chopped strand is easy to process during compounding, so it can be used together with thermoplastic resins (eg, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, etc.) or thermosetting resins for various electrical and electronic products, automobile parts, mechanical parts, etc. It can be applied as a reinforcement material.

<Glass fiber reinforced thermoplastic polymer composite material>

The present invention provides a glass fiber-reinforced thermoplastic polymer composite material including the glass fibers described above. The mechanical strength of the thermoplastic resin is reinforced by the glass fibers coated with the sizing composition according to the present invention, so that the mechanical strength of the composite material can be improved. The composite material can be processed into various shapes and applied to various fields such as airplane parts, ship parts, automobile parts, sports goods, and electrical and electronic products.

The thermoplastic resin is not particularly limited as long as it is known in the art, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, and polyphenylene sulfide.

The mixing ratio of the glass fiber and the thermoplastic resin is not particularly limited, and may be, for example, 10:90 to 60:40 in weight ratio, and another example 20:80 to 60:40 in weight ratio.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are only for facilitating the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

Sizing composition preparation

[Production Example 1-10]

According to the compositions of Tables 1 to 3 below, sizing compositions of each preparation example were prepared.

Polyurethane resin 1: pH 8, Mn 44,000, Mw 90,000, Tg -30 ℃

Polyurethane resin 2: pH 6.5, Mn 30,000, Mw 85,000, Tg -20 ℃

Polyurethane resin 3: pH 9, Mn 50,000, Mw 105,000, Tg -40 ℃

Polyurethane resin 4: pH 8, Mn 20,000, Mw 60,000, Tg -65 ℃

Polyurethane resin 5: pH 9, Mn 18,000, Mw 58,000, Tg -55 ℃

Epoxy Resin 1: O-cresol-novolac epoxy resin (epoxy equivalent 235 g/eq)

Epoxy resin 2: BPA-novolac epoxy resin (epoxy equivalent 230 g/eq)

Epoxy resin 3: novolac epoxy resin (epoxy equivalent 195 g/eq)

Epoxy resin 4: BPA-epoxy resin (epoxy equivalent 1,300 g/eq)

Amino silane: 3-Aminoproplytriethoxysilane

Epoxy silane: Gamma-glycidoxypropyltrimethoxy silane

Neutralizer: Acetic acid

Manufacture of glass fiber and thermoplastic polymer composite materials

[Experimental Example 1-10]

Each of the sizing compositions prepared in each preparation example was applied, and glass fibers fiberized to a diameter of 10 ± 1 μm were treated with a roll coating method through a bushing, cut into 4 mm length, and chopped strand glass of each experimental example fibers were made. The content of the sizing agent in the prepared glass fibers is 0.4 to 0.6 parts by weight based on 100 parts by weight (based on solid content) of the glass fibers.

30 parts by weight of each glass fiber and 70 parts by weight of polybutylene terephthalate resin (Chang Chun Plastic, PBT 1200) were mixed and extruded, and then injection specimens were prepared according to the ASTM D256 standard to measure physical properties.

[Evaluation of physical properties]

The physical properties of the thermoplastic polymer composite material prepared in each experimental example were measured by the following method, and the results are shown in Tables 4 and 5 below.

robbery

Tensile strength and impact strength were measured according to ASTM D638 and D256.

Pressure Cooker Test (PCT) Strength

After aging each specimen for 50 hours, 75 hours, and 100 hours, tensile strength was measured according to ASTM D638. Hydrolysis resistance was confirmed from the tensile strength retention rate.

As confirmed from the results of Tables 4 and 5, the sizing compositions of Experimental Examples 1-4 according to the present invention showed excellent initial strength, PCT strength and PCT retention rate. On the other hand, Experimental Example 5 using a polyurethane resin that does not satisfy the physical properties of the present invention, Experimental Example 6 using a BPA-type epoxy resin instead of a novolak-type epoxy resin, Experimental Example 7 using only one of amino silane or epoxy silane as a coupling agent , 8, in the case of the sizing compositions of Experimental Examples 9 and 10, in which the mixing ratio of amino silane and epoxy silane is out of the scope of the present invention, at least one of the physical properties measured was poor compared to the sizing composition of Experimental Examples 1-4. .

Claims (7)

A sizing composition comprising a film former comprising a polyurethane resin and a novolak-type epoxy resin and a silane coupling agent comprising an amino silane and an epoxy silane,
The number average molecular weight of the polyurethane resin is 20,000 to 60,000 g / mol,
A sizing composition wherein a mixing ratio (weight ratio, based on solid content) of the amino silane and the epoxy silane is 1:1 to 1.8. The sizing composition according to claim 1, wherein the polyurethane resin has a weight average molecular weight of 65,000 to 105,000 g/mol and a glass transition temperature of -60 to -20 °C. The sizing composition according to claim 1, wherein the epoxy equivalent of the novolak type epoxy resin is 150 to 300 g/eq. The sizing composition according to claim 1, wherein a mixing ratio (weight ratio, based on solid content) of the polyurethane resin and the novolak-type epoxy resin is 1:3 to 8. The sizing composition according to claim 1, comprising 70 to 95% by weight of the film former and 5 to 30% by weight of the silane coupling agent, based on the total solids of the sizing composition. Glass fibers surface-treated with the sizing composition according to claim 1 . A glass fiber-reinforced thermoplastic polymer composite material comprising the glass fiber according to claim 6.