JP2003112952A - Sizing agent for glass fiber containing magnesium chloride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sizing agent for glass fibers with which a glass fiber- reinforced thermoplastic resin having high tensile strength, shock resistance and water resistance can be obtained. SOLUTION: This sizing agent for glass fibers is composed of a non-volatile component and a volatile component. The non-volatile component contains a polyurethane resin, lubricant, silane coupling agent and magnesium chloride. The volatile component contains water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sizing agent for glass fibers, a glass fiber bundle in which a plurality of glass fiber filaments are bundled by a non-volatile component of the sizing agent for glass fibers, and the glass fiber bundle and a thermoplastic resin. The present invention relates to a glass fiber thermoplastic resin molded product containing.

[0002]

2. Description of the Related Art Thermoplastic resins are often insufficient in properties such as mechanical strength and impact resistance by themselves, and glass fibers are used in applications requiring high mechanical strength and impact resistance. What is added (glass fiber reinforced thermoplastic resin) is used. The glass fiber to be added is generally a glass fiber bundle obtained by bundling a plurality of glass fiber filaments, and such a glass fiber bundle is usually produced by bundling glass fiber filaments with a sizing agent. Therefore, in the glass fiber reinforced thermoplastic resin, there is a sizing agent near the interface between the glass fiber and the thermoplastic resin,
This has a great influence on the properties of the glass fiber reinforced thermoplastic resin. Therefore, it is necessary to design the sizing agent according to the properties required of the glass fiber reinforced thermoplastic resin.

As a sizing agent for improving the characteristics of the glass fiber reinforced thermoplastic resin, for example, JP-A-9-249 is known.
The sizing agent containing the pyrophosphate salt disclosed in Japanese Patent No. 434 and the sizing agent containing the tripolyphosphate salt disclosed in Japanese Patent Application Laid-Open No. 9-250088 are known. It is said that the mechanical strength and hot water resistance of the glass fiber reinforced thermoplastic resin are improved.

[0004]

However, due to the diversification of uses of glass fiber reinforced thermoplastic resins in recent years, higher mechanical strength (tensile strength, impact resistance, etc.) and water resistance are required. The glass fiber reinforced thermoplastic resin disclosed in the above publication and other known glass fiber reinforced thermoplastic resins cannot satisfy the requirements such as mechanical strength and water resistance. .

The present invention has been made in view of the above problems of the prior art, and is a glass fiber reinforced thermoplastic resin which exhibits not only high tensile strength and impact resistance but also excellent water resistance. An object of the present invention is to provide a sizing agent for glass fibers, which is capable of obtaining Another object of the present invention is to provide a glass fiber bundle using such a glass fiber sizing agent, and a glass fiber reinforced thermoplastic resin molded product containing the glass fiber bundle.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that magnesium chloride is added to an aqueous glass fiber sizing agent containing a polyurethane resin as a film-forming resin. As a result, they have found that the above object can be achieved, and completed the present invention.

That is, the glass fiber sizing agent of the present invention is a glass fiber sizing agent composed of a non-volatile component and a volatile component. The non-volatile component is a polyurethane resin, a lubricant, a silane coupling agent, and a chloride. It is characterized in that it contains magnesium and the volatile component contains water.

The glass fiber bundle of the present invention is characterized in that a plurality of glass fiber filaments are bundled by the glass fiber sizing agent of the present invention.
The glass fiber reinforced thermoplastic resin molded product of the present invention is characterized by being formed by molding the thermoplastic resin containing the glass fiber bundle of the present invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the sizing agent for glass fibers of the present invention comprises a non-volatile component and a volatile component,
The non-volatile component includes a polyurethane resin, a lubricant, a silane coupling agent, and magnesium chloride, and the volatile component includes water. In the present invention, the "non-volatile component" means
The component which does not volatilize by heating at 120 ° C. is referred to, and the “volatile component” means a component which volatilizes by such heating. Hereinafter, each of the components constituting the glass fiber sizing agent will be described in detail.

First, the urethane resin in the glass fiber sizing agent of the present invention will be described. The polyurethane resin that can be used in the present invention is a resin having a urethane bond capable of forming a film on the glass fiber at the drying temperature (room temperature to 150 ° C.) of the glass fiber sizing agent. Such a polyurethane resin has a minimum film forming temperature of 130.
℃ or less (preferably 80 ℃ or less, more preferably 60 ℃
The polyurethane resin having a temperature of 20 ° C. or less is particularly preferable.

Further, the polyurethane resin in the present invention preferably has the following properties as an aqueous dispersion (or dissolved product). That is, 2 g of an aqueous dispersion (or solution) of polyurethane resin in terms of solid content was applied on the surface of a glass plate and dried at 120 ° C. for 3 hours to form a dry film having a diameter of about 20 cm, and after leaving to cool, 1 cm.
It is preferable that the polyurethane resin is such that the dry film does not peel off from the glass plate when a cut is made in the shape of a square with a cutter knife. In addition, a dry film that is cut into a 1 cm square box is attached to an adhesive tape (Nichiban Co.,
It is preferable to use a polyurethane resin such that the dry film does not peel off from the glass plate when Cellotape CT-15) is attached and peeled off.

Such a polyurethane resin comprises a polyol such as a polyester polyol, a polyether polyol, a polycarbonate polyol, an olefinic polyol and the like, and a polyisocyanate such as an aromatic polyisocyanate, an aliphatic polyisocyanate and an alicyclic polyisocyanate in any equivalent amount. It can be obtained by reacting in a ratio. The terminal of the polyurethane resin may be an isocyanate group or a hydroxyl group, and these groups may be blocked by a known method. The main chain of the polyurethane resin may be modified by a known method.

The polyurethane resin in the present invention has, for example, a polyoxyethylene unit in its chemical structure and exhibits solubility and / or swellability in water contained in the sizing agent for glass fibers (hereinafter referred to as "water-soluble polyurethane"). resin"
Say. ), Or those that are not soluble or swellable in water and are dispersed or emulsified in water (hereinafter referred to as “water-dispersible polyurethane resin”). In the present invention, a water-dispersible polyurethane resin is preferable because it can reduce the viscosity even with the same solid content. Further, the water-dispersible polyurethane resin is preferably provided in the form of emulsion or dispersion.

Next, the lubricant in the glass fiber sizing agent of the present invention will be described. The sizing agent for glass fibers of the present invention contains a lubricant as an essential component. The lubricant in the present invention may be one that can protect the glass fibers from mechanical friction in the manufacturing process of glass fiber products such as glass fiber bundles. For example, a condensate of higher saturated fatty acid and higher saturated alcohol, etc. Synthetic oil of; polyethyleneimine;
Examples thereof include silicone oils such as polydimethylsiloxane. A particularly preferable lubricant that can be used in the present invention is a condensate of tetraethylenepentamine and stearic acid to which acetic acid is added to adjust the pH to 4.5 to 5.5.
The adjusted product (hereinafter, the solid content in the adjusted product is referred to as “TEPA / SA”). TEPA / SA
The molar ratio of the reaction ratio of tetraethylenepentamine to stearic acid is preferably former / latter = 1/1 to 1/2. By using such a lubricant, it becomes possible to protect the glass fibers from mechanical friction, reduce the friction between the glass fiber filaments in the glass fiber bundle, and further impart flexibility to the glass fibers. .

Next, the silane coupling agent in the glass fiber sizing agent of the present invention will be described. The silane coupling agent used in the present invention is a silane compound having a hydrolyzable group and a hydrophobic group (organic group), and examples of such a compound include vinyltriethoxysilane, vinyltrimethoxysilane, and γ- (methacryloyloxy). Propyl) trimethoxysilane and other silane coupling agents having unsaturated double bonds; β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldi Silane coupling agent having an epoxy group such as ethoxysilane; silane coupling agent having a mercapto group such as γ-mercaptopropyltrimethoxysilane; γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyl Trimethoxysilane , N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane and other silane coupling agents having an amino group. In the present invention, it is preferable to use a silane coupling agent having an amino group.

Since the silane coupling agent has the hydrolyzable silicon group having reactivity with the glass fiber as described above, and the hydrophobic group (organic group) having affinity with the thermoplastic resin, By using the sizing agent for glass fibers of the present invention containing a silane coupling agent, the interfacial adhesion between the glass fiber bundle and the thermoplastic resin can be improved.

Next, the magnesium chloride in the glass fiber sizing agent of the present invention will be described. The sizing agent for glass fibers of the present invention is characterized by containing magnesium chloride. In the present invention, magnesium chloride refers to anhydrous magnesium chloride (MgCl ₂ ) or hydrated magnesium chloride (dihydrate, tetrahydrate, hexahydrate, octahydrate, dodecahydrate, etc.). Since such magnesium chloride has water solubility, in the sizing agent for glass fibers of the present invention, magnesium chloride exists mainly in a state of being dissolved in water.

It is considered that magnesium chloride, which is an essential component of the sizing agent for glass fibers of the present invention, greatly contributes to the improvement of the tensile strength, impact resistance and water resistance of the glass fiber reinforced thermoplastic resin. Instead of magnesium chloride, colloidal silica, sodium pyrophosphate, a glass fiber sizing agent using a metal salt such as sodium tripolyphosphate, the resulting glass fiber reinforced thermoplastic resin is poor in tensile strength and water resistance, In the present invention, it is considered that the above properties can be specifically obtained by combining magnesium chloride with other essential components. Although the reason why such improvement in properties is obtained is not clear, it is assumed that one of the reasons is that magnesium chloride changes the crystal structure of the thermoplastic resin.

The content of the above essential components in the glass fiber sizing agent of the present invention is arbitrary, but a polyurethane resin,
The content ratios of the lubricant, the silane coupling agent and the magnesium chloride are 10 to 80% by weight and 0.1 to 0.1% by weight, respectively, based on the total weight of the non-volatile components of the sizing agent for glass fibers.
It is preferably 10% by weight, 1 to 30% by weight and 10 to 80% by weight.

If the content ratio of the polyurethane resin is less than the above lower limit value, the strength for converging the glass fiber filaments tends to be insufficient, and if it exceeds the above upper limit value, the thermoplastic resin containing the glass fiber bundles is used. Gas may be generated when molding the resin. When the content ratio of the lubricant is less than the lower limit value, the glass fiber filament tends to be insufficiently protected from mechanical friction and the like, and when the content exceeds the upper limit value, when the glass fiber bundle is dried. May be colored, and the strength of the molded product may decrease.

On the other hand, if the content ratio of the silane coupling agent is less than the above lower limit value, the interfacial adhesion between the glass fiber bundle and the thermoplastic resin tends to be insufficient, and if it exceeds the above upper limit value. In some cases, the strength of the thermoplastic resin molded product containing the glass fiber bundle is reduced. When the content ratio of magnesium chloride is less than the lower limit value, the tensile strength of the glass fiber reinforced thermoplastic resin, the impact resistance and the degree of improvement in water resistance tend to be small,
If the amount exceeds the upper limit, the focusing property of the glass fiber bundle tends to decrease.

In the present invention, the content ratios of the polyurethane resin, the lubricant, the silane coupling agent and the magnesium chloride are 15 to 60% by weight and 0 to 0% respectively based on the total weight of the non-volatile components of the sizing agent for glass fibers. .5 to 5
%, More preferably 5 to 25% by weight and 20 to 70% by weight, respectively, 20 to 40% by weight, 1 to
More preferably, they are 3% by weight, 10 to 20% by weight and 40 to 60% by weight.

The non-volatile component in the glass fiber sizing agent of the present invention is 1 based on the total weight of the glass fiber sizing agent.
-20 wt% is preferable, and 2-10 wt% is more preferable. When the content ratio of the non-volatile components is less than 1% by weight, the amount of the glass fiber sizing agent attached to the glass fibers is reduced by one application, and the production cost is increased because the application must be performed multiple times. In some cases, if the amount exceeds 20% by weight, the viscosity may increase and problems may occur in coating properties. The content ratio of water in the volatile component (a component other than the non-volatile component) is preferably 90% by weight or more, and more preferably 95% by weight or more.

The sizing agent for glass fibers of the present invention may further contain additional components such as a pH adjuster, an antistatic agent and an emulsifier in addition to the above-mentioned essential components. Further, it may contain a small amount of alcohol such as methanol, ethanol or isopropanol, or other organic solvent.

As the pH adjusting agent, a weak acid such as acetic acid is preferable, and by adding the pH adjusting agent, p of the sizing agent for glass fiber is added.
It is preferable to adjust H to 3.0 to 5.0. By adjusting the pH, the hydrolysis of the silane coupling agent can be promoted.

Examples of the antistatic agent include polyoxyethylene alkylamine, alkyl sulfonate, and quaternary ammonium chloride. By adding an antistatic agent to the sizing agent for glass fibers, it is possible to reduce the generation of static electricity generated in the glass fibers. The content of the antistatic agent is preferably 1 to 3% by weight based on the total weight of the non-volatile components of the sizing agent for glass fibers.

As the emulsifier, anionic surfactants such as sodium dodecylbenzene sulfonate, cationic surfactants such as aliphatic quaternary ammonium salts, amphoteric surfactants such as carboxybetaine, polyoxyethylene polyalkyl ethers, etc. The above nonionic surfactants and the like can be used. The content of the emulsifier is preferably 0.5 to 2% by weight based on the total weight of the non-volatile components of the glass fiber sizing agent.

The sizing agent for glass fibers of the present invention is prepared by preparing an aqueous emulsion or dispersion or an aqueous solution of the above-mentioned polyurethane resin, and adding the above-mentioned lubricant,
Add silane coupling agent and magnesium chloride,
It is preferable to manufacture by adding the above-mentioned additional components, an organic solvent, etc. as needed. The silane coupling agent may be provided as an alcohol solution, and in that case, the alcohol component can be added without removing the alcohol component.

Next, the glass fiber bundle of the present invention will be described. The glass fiber bundle of the present invention comprises a plurality of glass fiber filaments bundled by the above-mentioned glass fiber sizing agent. Here, the glass fiber bundle of the present invention is composed of a plurality of glass fiber filaments and a non-volatile component of the glass fiber sizing agent of the present invention, the non-volatile component is present between the plurality of glass fiber filaments, glass It preferably functions as an adhesive (binder) for bundling the fiber filaments. In this case, the non-volatile component preferably has a function of protecting the glass fiber by coating the outer periphery of the glass fiber filament as a continuous or discontinuous film.

It is sufficient that the non-volatile component has such strength as to keep the glass fiber filaments in a bundle when the glass fiber bundle is used, and need not be uniformly distributed in the glass fiber bundle. . That is, from the viewpoint of the adhesiveness between the glass fiber filaments, the non-volatile component is preferably distributed at a substantially uniform concentration from the outer edge portion of the glass fiber bundle toward the central portion, for example, the concentration of the outer edge portion is Even if the concentration in the central portion is high and the concentration in the central portion is low, the glass fiber filaments can be retained and pose no practical problem. Therefore, the glass fiber bundle having such a configuration can be adopted in the present invention.

The glass fiber filaments used in the glass fiber bundle of the present invention preferably have a filament diameter of 3 to 23 μm, and the glass fiber bundle is preferably a bundle of 25 to 4000 such glass fiber filaments. Examples of the glass composition of the glass fiber filaments include E glass, S glass and C glass. The ratio of the total weight of the glass fiber filaments to the weight of the non-volatile components of the sizing agent for glass fibers in the glass fiber bundle of the present invention is 0.2 to the latter 100 parts by weight.
5.0 parts by weight is preferable, and 0.5 to 2.0 parts by weight is more preferable. Embodiments of the glass fiber bundles of the present invention include glass fiber yarns and glass fiber rovings.

The glass fiber bundle of the present invention is obtained, for example, by applying a glass fiber sizing agent to a glass fiber filament drawn from a platinum nozzle (bushing) using a roller type applicator, a belt type applicator, etc. It can be manufactured by bundling glass fiber filaments by bundling with, and then drying this at room temperature to 150 ° C. to remove volatile components such as water. If necessary, twisting may be performed before drying.

The glass fiber bundle obtained by such a method is a long fiber, but in the present invention, the glass fiber bundle is characterized in that a plurality of glass fiber filaments are bundled by the glass fiber sizing agent. Therefore, a glass fiber bundle in which the fiber length of the glass fiber filament is several to several tens mm (hereinafter referred to as "short fiber length glass fiber bundle").
Can also be used. By using the glass fiber bundle having such a fiber length, it becomes easy to produce the glass fiber reinforced thermoplastic resin and the dispersibility of the glass fiber bundle in the obtained glass fiber reinforced thermoplastic resin is improved.

Fiber length of short fiber length glass fiber bundle is 1 to 25
mm is preferable, and 1.5 to 13 mm is more preferable. Fiber length of short fiber length glass fiber bundle is 1
If it is less than mm, fluff is generated during the production of short fiber glass fiber bundles, which tends to increase the bulkiness and decrease the productivity. If it exceeds 25 mm, the short fiber glass fiber bundles are entangled with each other and are bulky. The productivity tends to decrease.

The short fiber long glass fiber bundle can be produced by producing the glass fiber bundle (long fiber) by the above-mentioned method and then cutting the glass fiber bundle into 1 to 25 mm. Glass fiber chopped strands called short fiber length glass fiber bundle by the method).

Next, the glass fiber reinforced thermoplastic resin molded product of the present invention will be described. The glass fiber reinforced thermoplastic resin molded product of the present invention is obtained by molding a thermoplastic resin containing the above-mentioned glass fiber bundle (long fiber and / or short fiber long glass fiber bundle). When the glass fiber reinforced thermoplastic resin molded product contains long fibers of a glass fiber bundle, the long fibers are preferably a braid.

As the thermoplastic resin constituting the glass fiber reinforced thermoplastic resin molding, polyamide resin (nylon 6, nylon 66, nylon 10, nylon 12, nylon 6T, nylon 9T, nylon 46, etc.), copolymer nylon, Crystalline polymers such as PET, PBT, polypropylene and polyethylene can be used. In the present invention,
It is preferable to use, as the thermoplastic resin, a polyamide resin having a relatively high water absorption property and the physical properties of which tend to change due to contact with water. This is because when the polyamide resin is reinforced with the glass fiber bundle using the glass fiber sizing agent of the present invention, the water resistance is significantly improved, and the tensile strength and the impact resistance are excellent.

The glass fiber reinforced thermoplastic resin molded product of the present invention preferably contains 30 to 200 parts by weight, and preferably 40 to 150 parts by weight of the glass fiber bundle of the present invention with respect to 100 parts by weight of the thermoplastic resin. More preferably.
Incidentally, the glass fiber reinforced thermoplastic resin molded product of the present invention,
It may further contain an additive component such as a filler.

In the glass fiber reinforced thermoplastic resin molded product of the present invention, the weight of magnesium chloride in the glass fiber bundle is 0.05 to 1.5 parts by weight (more preferably 100 parts by weight of the thermoplastic resin). Is 0.1-1.
It is preferably 0 parts by weight, more preferably 0.1 to 0.5 parts by weight). When the weight of magnesium chloride is within the above range, the glass fiber reinforced thermoplastic resin is particularly excellent in water resistance, tensile strength and impact resistance.
That is, when the weight of magnesium chloride is less than 0.05 parts by weight, it tends to be difficult to obtain the effect of improving the above characteristics, and when it exceeds 1.5 parts by weight, the amount of addition is too large to add. It may be wasted.

The method for molding the glass fiber reinforced thermoplastic resin molded product of the present invention is not particularly limited, but the glass fiber reinforced thermoplastic resin molded product of the present invention is the glass fiber bundle (short fiber long glass) of the present invention. It is preferably obtained by pelletizing a compound of a fiber bundle) and a thermoplastic resin and performing injection molding.

The glass fiber thermoplastic resin of the present invention described above not only exhibits high tensile strength and impact resistance, but also is excellent in water resistance, and therefore is particularly preferably used in applications such as radiator tanks. You can

[0042]

EXAMPLES Hereinafter, preferred examples of the present invention will be described in more detail, but the present invention is not limited to these examples.

[Preparation of sizing agent for glass fiber] (Example 1) Pure water 8k prepared by adding acetic acid to pH 5
g is γ-aminopropyltriethoxysilane which is a silane coupling agent (manufactured by Nippon Unicar Co., A1100)
0.1 kg was added. To this, polyurethane resin emulsion (Dainippon Ink and Chemicals, Inc .: 1660NS,
Polyurethane resin concentration: 40% by weight) (0.4 kg) was added, and the mixture was stirred at room temperature. 0.3 kg of magnesium chloride anhydrous salt was added to the resulting solution, and TEPA / SA as a lubricant.
(Molar ratio of tetraethylenepentamine and stearic acid: former / latter = 1/2) 0.01 kg was added, and finally pure water was added to make the total weight 10 kg to obtain a glass fiber sizing agent. .

Comparative Example 1 A sizing agent for glass fibers was obtained in the same manner as in Example 1 except that magnesium chloride was not used.

Comparative Examples 2 to 4 Glass fiber sizing agents were obtained in the same manner as in Example 1 except that the same weight of colloidal silica, sodium tripolyphosphate and sodium pyrophosphate were added instead of magnesium chloride. It was
The colloidal silica was added as a 20 wt% colloidal silica aqueous solution (CT100, manufactured by Asahi Denka Co., Ltd., solid content 20 wt%).

[Production of Glass Fiber Bundle and Glass Fiber Chopped Strand] (Example 2 and Comparative Examples 5 to 8) Example 1 and Comparative Examples 1 to 1
Each of the sizing agents for glass fibers obtained in No. 4 had a diameter of 1
Apply to a bundle of 1600 1 μm glass fiber filaments (Nitto Boseki Co., Ltd .: 240TEX),
It dried at 0 degreeC and obtained the glass fiber bundle. In this case, 0.95 parts by weight of the non-volatile component of the glass fiber sizing agent was attached to 100 parts by weight of the glass fiber filaments. Then, the obtained glass fiber bundle is length 3
It cut | disconnected to mm and produced the glass fiber chopped strand. The glass fiber chopped strands obtained using the sizing agent for glass fibers obtained in Example 1 and Comparative Examples 1 to 4 correspond to Example 2 and Comparative Examples 5 to 8, respectively.

[Production of Glass Fiber Reinforced Polyamide Resin Molded Product] (Example 3 and Comparative Examples 9 to 12) Example 2 and Comparative Example 5
~ 8 glass fiber chopped strands, nylon 6
(Ube Industries, Ltd., 1015B) pellets were mixed so as to have a glass content of 33% by weight, pelletized by an extruder, and then a glass fiber reinforced polyamide resin molded product was obtained by an injection molding machine. The weight of magnesium chloride is 0.25 with respect to 100 parts by weight of nylon 6.
It was part by weight. Moreover, the glass fiber reinforced polyamide resin using the sizing agent for glass fibers obtained in Example 1 and Comparative Examples 1 to 4 corresponds to Example 3 and Comparative Examples 9 to 12, respectively.

[Performance Test of Glass Fiber Reinforced Polyamide Resin Molded Product] (Normal Tensile Strength Test) The glass fiber reinforced polyamide resin molded product obtained in Example 3 and Comparative Examples 9 to 12 was used as AS.
TMI No. 1 dumbbell was molded and used as a test piece
According to STM D638, the normal tensile strength (MPa) of the glass fiber reinforced polyamide resin molded product at 25 ° C was measured under dry conditions. The tensile strength was the maximum strength when the test piece was deformed at a deformation rate of 5 mm / min.

(Water Resistance Test-Water Absorption Tensile Strength Test) Similar to the above “Tensile Strength Test”, Example 3 and Comparative Examples 9 to
A test piece of the glass fiber reinforced polyamide resin molded product obtained in 12 was prepared, and the test piece was held at 120 ° C. for 15 hours (2 atm, saturated steam) with a pressure cooker,
Immediately after taking out from the pressure cooker, the tensile strength (MPa) was measured in the same manner as the above-mentioned “tensile strength test”, and the water resistance test was performed.

(Izod impact test-with notch) The glass fiber reinforced polyamide resin moldings obtained in Example 3 and Comparative Examples 9 to 12 were molded to have a thickness of 6.4 mm and a width of 12.7 m.
An impact test was conducted in accordance with ASTM D256 by using a test piece formed by molding a sample having a length of m and a length of 64 mm and forming a notch in the test piece. The hammer lifting angle was 150 ° and the hammer capacity was 20 kg · cm.

(Izod Impact Test-No Notch) The glass fiber reinforced polyamide resin moldings obtained in Example 3 and Comparative Examples 9 to 12 were molded to have a thickness of 6.4 mm and a width of 12.7 m.
An impact test was conducted according to ASTM D256 as a test piece without forming a notch in the molded product. The hammer lifting angle was 150 ° and the hammer capacity was 20 kg · cm.

The results of the normal tensile strength test, the water resistance test (water absorption tensile strength test), the Izod impact test (with notch) and the Izod impact test (with notch) are shown as the composition of the non-volatile components of the sizing agent for glass fiber ( Weight part of each non-volatile component in 100 parts by weight of the sizing agent for glass fiber, weight% of each non-volatile component based on the total weight of the non-volatile component),
The results are shown in Table 1. In addition, Example 3 and Comparative Example 9-
In the glass fiber reinforced polyamide resin molded product obtained in 12, the glass fiber sizing agents of Example 1 and Comparative Examples 1 to 4 are used, respectively.

[0053]

[Table 1]

[0054]

As described above, according to the present invention,
A sizing agent for glass fibers capable of obtaining a glass fiber-reinforced thermoplastic resin that exhibits high tensile strength and impact resistance as well as excellent water resistance. Further, it becomes possible to provide a glass fiber bundle using such a sizing agent for glass fibers, and a glass fiber reinforced thermoplastic resin molded product containing the glass fiber bundle.

Claims (7)

[Claims] 1. A sizing agent for glass fibers comprising a non-volatile component and a volatile component, wherein the non-volatile component contains a polyurethane resin, a lubricant, a silane coupling agent and magnesium chloride, and the volatile component is , A sizing agent for glass fibers, which contains water. 2. The content ratio of the magnesium chloride is 10 to 80% by weight based on the total weight of the non-volatile components.
The sizing agent for glass fibers according to claim 1, wherein 3. A glass fiber bundle comprising a plurality of glass fiber filaments bundled by the glass fiber sizing agent according to claim 1. 4. The glass fiber bundle according to claim 3, wherein the fiber length of the glass fiber filament is 1 to 25 mm. 5. A glass fiber reinforced thermoplastic resin molded article, characterized by being formed by molding a thermoplastic resin containing the glass fiber bundle according to claim 3 or 4. 6. The glass fiber reinforced thermoplastic resin molded product according to claim 5, wherein the thermoplastic resin is a polyamide resin. 7. The glass according to claim 5, wherein the weight of magnesium chloride in the glass fiber bundle is 0.05 to 1.5 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Fiber reinforced thermoplastic resin molding.