JP7068737B1 - Sizing agents for inorganic fibers, inorganic fibers, their manufacturing methods, and composite materials - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sizing agent for an inorganic fiber, an inorganic fiber, a method for producing the same, and a composite material capable of achieving both an effect of reducing adhesion spots on the inorganic fiber and an effect of improving the focusing property. The sizing agent for inorganic fibers of the present invention is characterized by containing a resin (A) and a fluorine-containing surfactant (B) having a perfluoroalkenyl group in the molecule. The inorganic fiber of the present invention is characterized in that the sizing agent for the inorganic fiber is attached. The method for producing an inorganic fiber of the present invention is characterized by comprising a step of adhering the sizing agent for inorganic fiber to the inorganic fiber. Further, the composite material of the present invention is characterized by containing the inorganic fiber and the matrix resin. [Selection diagram] None

Description

The present invention relates to a sizing agent for inorganic fibers containing a fluorine-containing surfactant, an inorganic fiber, a method for producing the same, and a composite material.

In general, a fiber-reinforced resin composite material is known as a material containing an inorganic fiber such as carbon fiber and a matrix resin such as a thermoplastic resin or a thermosetting resin as a base material, and is widely used in various fields such as building materials and transportation equipment. There is. A treatment of adhering a sizing agent to the inorganic fiber is performed in order to improve the adhesiveness of the interface between the inorganic fiber such as carbon fiber and the matrix resin.

Conventionally, for example, a sizing agent for inorganic fibers used for reinforcing the matrix resin disclosed in Patent Document 1 has been known. Patent Document 1 discloses a sizing composition for carbon fibers containing an alkylene oxide adduct of distyrenated phenol, an alkylene oxide adduct of tristyrenated phenol, and a sizing agent.

Japanese Unexamined Patent Publication No. 2019-99942

However, the sizing agent for inorganic fibers of Patent Document 1 is insufficient in both the effect of reducing adhesion spots on the inorganic fibers and the effect of improving the focusing property.

As a result of research to solve the above-mentioned problems, the present inventors have found that a sizing agent for inorganic fibers containing a specific fluorine-containing surfactant and a resin is correctly suitable.
In order to solve the above problems, the gist of the sizing agent for inorganic fibers according to one aspect of the present invention is to contain a resin (A) and the following fluorine-containing surfactant (B).

Fluorine-containing surfactant (B): A surfactant having a perfluoroalkenyl group in the molecule.
In the sizing agent for inorganic fibers, the content ratio of the fluorine-containing surfactant (B) in the non-volatile content of the sizing agent for inorganic fibers may be 10 ppm or more and 60,000 ppm or less.

In the sizing agent for inorganic fibers, the fluorine-containing surfactant (B) may contain a polyoxyalkylene perfluoroalkenyl ether.
In the sizing agent for inorganic fibers, the resin (A) is an epoxy resin, vinyl ester resin, polyamide resin, polyolefin resin, polyurethane resin, polycarbonate resin, polyester resin, PEEK resin, fluororesin, phenoxy resin, phenol resin, BMI. It may contain at least one selected from a resin, a polyimide resin, a polyimide resin precursor, a polyether sulfone resin, and a polyether ester resin.

In the sizing agent for inorganic fibers, when the total mass of the non-volatile component of the resin (A) is 100 parts by mass, the fluorine-containing surfactant (B) is added in an amount of 0.001 part by mass or more and 6 parts by mass or less. It may be contained.

The sizing agent for inorganic fibers may further contain a surfactant (C) (excluding those corresponding to the fluorine-containing surfactant (B)).
Assuming that the total content of the non-volatile content of the resin (A) and the surfactant (C) is 100 parts by mass in the sizing agent for inorganic fibers, the non-volatile content of the resin (A) is 20 parts by mass or more and 99 parts by mass. The surfactant (C) may be contained in an amount of 1 part by mass or less and 80 parts by mass or less.

In order to solve the above problems, in the inorganic fiber of another aspect of the present invention (excluding the filter medium for an air filter in which a binder and a fluorine-based surfactant are attached to the glass fiber constituting the filter medium) , the inorganic fiber is used. The gist is that the sizing agent for use is attached.
In order to solve the above problems, the gist of the method for producing an inorganic fiber according to another aspect of the present invention is to include a step of adhering the sizing agent for the inorganic fiber to the inorganic fiber.

In order to solve the above problems, in another aspect of the present invention, the resin in the sizing agent for inorganic fibers, which is a composite material containing the inorganic fibers and the matrix resin, is an epoxy resin, a polyurethane resin, or a polyester resin. , A phenoxy resin, and at least one selected from a polyether ester resin, and the gist is that the matrix resin is an epoxy resin.

In order to solve the above problems, in another aspect of the present invention, the composite material containing the inorganic fiber and the matrix resin, the resin in the sizing agent for the inorganic fiber is a polyurethane resin, a polyimide resin precursor, and It contains at least one selected from polyamide resins, and the gist is that the matrix resin is a polyamide resin.

In order to solve the above problems, in another aspect of the present invention, the composite material containing the inorganic fiber and the matrix resin, wherein the resin in the sizing agent for the inorganic fiber contains a vinyl ester resin, and the matrix resin is used. The gist is that is a vinyl ester resin.

In order to solve the above problems, in another aspect of the present invention, the composite material containing the inorganic fiber and the matrix resin, the resin in the sizing agent for the inorganic fiber contains a polyolefin resin, and the matrix resin is The gist is that it is a polypropylene resin.

According to the present invention, it is possible to achieve both an improvement in the effect of reducing adhesion spots on inorganic fibers and an effect of improving the focusing property.

The schematic diagram of the composite material interface property evaluation apparatus for adhesiveness evaluation in an Example column.

<First Embodiment>
First, a first embodiment embodying a sizing agent for inorganic fibers (hereinafter, also referred to as a sizing agent) according to the present invention will be described. The sizing agent contains the resin (A) and the predetermined fluorine-containing surfactant (B).

(Resin (A))
The resin (A) used for the sizing agent of the present embodiment is appropriately selected from known ones depending on the use of the inorganic fiber to which the sizing agent is applied. Specific examples of the resin include epoxy resin, vinyl ester resin, polyamide resin, polyolefin resin, polyurethane resin, polycarbonate resin, polyester resin, PEEK resin, fluororesin, phenoxy resin, phenol resin, BMI resin, polyimide resin, and polyimide resin. Examples thereof include precursors, polyether sulfone resins, polyether ester resins and the like. As these resins, one kind of resin may be used alone, or two or more kinds of resins may be used in combination.

Specific examples of the resin include epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd .: trade name: jER828, jER1002, jER1001), polyurethane resin (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: trade name: Superflex 740), and polypropylene resin (Maruyoshi Chemical Co., Ltd.). Company: Product name: MGP-1650), Polypropylene resin (Toho Chemical Industry Co., Ltd .: Product name: Hi-Tech P-9018), Polyester resin (Toyo Spinning Co., Ltd .: Product name: Byronal MD-1480), Phenoxy resin (Nittetsu) Chemical & Materials Co., Ltd .: Trade name: YP-50S), 3,3', 4,4'-biphenyltetracarboxylic acid anhydride and diaminodiphenyl ether polyimide resin precursor, polyamide resin (Toray Co., Ltd .: trade name: AQ) Nylon P-95), bisphenol A ethylene oxide 2 mol adduct and fumaric acid polyether ester resin, epoxy resin and methacrylic acid vinyl ester resin, polyethylene glycol with average molecular weight 2000, dimethyl terephthalate and lauryl alcohol copolymer (Polyether ester resin) and the like.

When the inorganic fiber is applied to the composite material, the type of resin to be blended in the sizing agent is selected in consideration of the type of the base material constituting the composite material from the viewpoint of improving adhesiveness and recyclability. Is preferable. When the matrix resin is applied to a composite material of an epoxy resin, the resin in the sizing agent is preferably at least one selected from an epoxy resin, a polyurethane resin, a polyester resin, a phenoxy resin, and a polyether ester resin. When the matrix resin is applied to a composite material of a polyamide resin, the resin in the sizing agent is preferably at least one selected from a polyurethane resin, a polyimide resin precursor, and a polyamide resin. When the matrix resin is applied to a composite material of vinyl ester resin, the resin in the sizing agent preferably contains vinyl ester resin. When the matrix resin is applied to a polypropylene resin composite material, the resin in the sizing agent preferably contains a polyolefin resin.

(Fluorine-containing surfactant (B))
As the fluorine-containing surfactant (B) used in the sizing agent of the present embodiment, a surfactant having a perfluoroalkenyl group in the molecule is applied. Further, the fluorine-containing surfactant (B) used in the sizing agent of the present embodiment preferably contains polyoxyalkylene perfluoroalkenyl ether. With such a configuration, the adhesiveness between the matrix resin and the inorganic fiber can be improved.

Specific examples of the fluorine-containing surfactant (B) include polyoxyalkylene perfluoroalkenyl ether (manufactured by Neos Co., Ltd .: trade name: Futergent 215M) to which an average of 15 mol of ethylene oxide has been added, and 12 mol of ethylene oxide to which an average of 12 mol has been added. Polyoxyalkylene perfluoroalkenyl ether (manufactured by Neos: trade name Futergent 212M), polyoxyalkylene perfluoroalkenyl ether with an average of 8 mol of ethylene oxide added (manufactured by Neos: trade name Futergent 251), ethylene oxide is average Polyoxyalkylene perfluoroalkenyl ether with 18 mol added (Neos: trade name: Futergent FTX-218), perfluoroalkenyl oxybenzenesulfonate sodium (Neos: trade name: Futergent 100), perfluoroalkenyl trialkyl Examples thereof include ammonium bromide (manufactured by Neos Co., Ltd .: trade name: ethylene oxide 320). As these fluorine-containing surfactants (B), one kind of fluorine-containing surfactant may be used alone, or two or more kinds of fluorine-containing surfactants may be used in combination.

In the sizing agent, the lower limit of the content ratio of the fluorine-containing surfactant (B) in the non-volatile content of the sizing agent is preferably 10 ppm or more, more preferably 30 ppm or more. When the content ratio is 10 ppm or more, the effect of reducing adhesion spots on the inorganic fibers can be further improved. In the sizing agent, the upper limit of the content ratio of the fluorine-containing surfactant (B) in the non-volatile content of the sizing agent is preferably 60,000 ppm or less, more preferably 50,000 ppm or less. When the content ratio is 60,000 ppm or less, the adhesiveness between the matrix resin as the base material and the inorganic fiber can be improved. A range in which the above upper and lower limits are arbitrarily combined is also assumed. The non-volatile content is determined from the mass of the absolute dry matter obtained by heat-treating the object at 105 ° C. for 2 hours to sufficiently remove volatile substances (hereinafter, the same applies).

When the total mass of the non-volatile content of the resin (A) is 100 parts by mass in the sizing agent, the lower limit of the content ratio of the fluorine-containing surfactant (B) is preferably 0.001 part by mass or more, more preferably. It is 0.005 part by mass or more. When the content ratio is 0.001 part by mass or more, the effect of reducing adhesion spots on the inorganic fibers can be further improved. When the total mass of the non-volatile component of the resin (A) in the sizing agent is 100 parts by mass, the upper limit of the content ratio of the fluorine-containing surfactant (B) is preferably 6 parts by mass or less. When the content ratio is 6 parts by mass or less, the adhesiveness between the matrix resin as the base material and the inorganic fiber can be improved. A range in which the above upper and lower limits are arbitrarily combined is also assumed.

(Surfactant (C))
If necessary, the sizing agent may further contain a surfactant (C) (excluding those corresponding to the fluorine-containing surfactant (B)). By blending the surfactant (C), the emulsification stability of the sizing agent can be improved. Examples of the surfactant (C) include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. As these surfactants (C), one kind of surfactant may be used alone, or two or more kinds of surfactants may be used in combination.

As the nonionic surfactant (C), known ones can be appropriately adopted. Specific examples of the nonionic surfactant (C) include (1) a compound obtained by adding an alkylene oxide having 2 to 4 carbon atoms to (1) an organic acid, an organic alcohol, an organic amine and / or an organic amide, for example, polyoxyethylene di. Lauric acid ester, polyoxyethylene oleic acid ester, polyoxyethylene oleic acid diester, polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene lauryl ether methyl ether, polyoxyethylene polyoxypropylene lauryl ether, polyoxypropylene Lauryl ether Methyl ether, polyoxyethylene oleyl ether, polyoxybutylene oleyl ether, polyoxyethylene polyoxypropylene nonyl ether, polyoxypropylene nonyl ether, polyoxyethylene polyoxypropylene octyl ether, ethylene oxide adduct of 2-hexylhexanol , Polyoxyethylene 2-ethyl-1-hexyl ether, polyoxyethylene isononyl ether, polyoxyethylene dodecyl ether, compound obtained by adding ethylene oxide to secondary dodecyl alcohol, polyoxyethylene tridecyl ether, polyoxyalkylene tetradecyl Ether-type nonionic surfactants such as ether, polyoxyethylene laurylamino ether, polyoxyethylene lauroamide ether, polyoxyalkylene tristyrene phenyl ether, (2) polyoxyalkylene sorbitan triolate, polyoxyalkylene palm oil, Polyoxyalkylene polyvalent polyoxyalkylene polyvalent such as maleic acid ester, stearic acid ester, or oleic acid ester of polyoxyalkylene hardened bean oil, polyoxyalkylene hardened bean oil, polyoxyalkylene hardened bean oil trioctanoate, polyoxyalkylene hardened bean oil. Alcohol fatty acid ester type nonionic surfactant, (3) Alkylamide type nonionic surfactant such as stearate diethanolamide, diethanolamine monolauroamide, (4) Polyoxyethylene diethanolamine monooleylamide, polyoxyethylene laurylamine, Examples thereof include polyoxyalkylene fatty acid amide-type nonionic surfactants such as polyoxyethylene beef ether.

As the anionic surfactant, known ones can be appropriately adopted. Specific examples of the anionic surfactant include (1) phosphate esters of aliphatic alcohols such as (1) lauryl phosphate ester salt, cetyl phosphate ester salt, octyl phosphate ester salt, oleyl phosphate ester salt, and stearyl phosphate ester salt. Salt, (2) At least one selected from ethylene oxide and propylene oxide for aliphatic alcohols such as polyoxyethylene lauryl ether phosphate ester salt, polyoxyethylene oleyl ether phosphate ester salt, and polyoxyethylene stearyl ether phosphate ester salt. Phosphate ester salt with alkylene oxide added, (3) Lauryl sulfonate, myristyl sulfonate, cetyl sulfonate, oleyl sulfonate, stearyl sulfonate, tetradecane sulfonate, dodecylbenzene sulfonate , An aliphatic sulfonate such as a secondary alkyl sulfonic acid (C13-15) salt or an aromatic sulfonate, (4) Sulfate of an aliphatic alcohol such as a lauryl sulfate ester salt, an oleyl sulfate ester salt, and a stearyl sulfate ester salt. Ester salts, (5) Polyoxyethylene lauryl ether sulfate ester salts, polyoxyalkylene (polyoxyethylene, polyoxypropylene) lauryl ether sulfate ester salts, polyoxyethylene oleyl ether sulfate ester salts, and other aliphatic alcohols with ethylene oxide and Sulfate ester salt with at least one alkylene oxide added selected from propylene oxide, (6) sesame oil fatty acid sulfate ester salt, sesame oil fatty acid sulfate ester salt, tall oil fatty acid sulfate ester salt, soybean oil fatty acid sulfate ester salt, rapeseed oil fatty acid sulfate Esters, palm oil fatty acid sulfates, pig fat fatty acid sulfates, beef fat fatty acid sulfates, whale oil fatty acid sulfates and other fatty acid sulfates, (7) castor oil sulfates, sesame oil sulfates , Thor oil sulfate, soybean oil sulfate, rapeseed oil sulfate, palm oil sulfate, pork fat sulfate, beef fat sulfate, whale oil sulfate, etc. Examples thereof include sulfate ester salts, (8) fatty acid salts such as laurate, oleate and stearate, and (9) sulfosuccinic acid ester salts of aliphatic alcohols such as dioctyl sulfosuccinate. Examples of the counterion of the anionic surfactant include alkali metal salts such as potassium salt and sodium salt, and alkanolamine salts such as ammonium salt and triethanolamine.

As the cationic surfactant, known ones can be appropriately adopted. Specific examples of the cationic surfactant include lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, didecyldimethylammonium chloride, 1,2-dimethylimidazole, triethanolamine and the like. Be done.

As the amphoteric tenside agent, known amphoteric surfactants can be appropriately adopted. Specific examples of the amphoteric tenside include a betaine-type amphoteric tenside.
Assuming that the total content of the non-volatile content of the resin (A) and the surfactant (C) in the sizing agent is 100 parts by mass, the non-volatile content of the resin (A) is 20 parts by mass or more and 99 parts by mass or less and the surfactant is active. It is preferable to contain the agent (C) in a proportion of 1 part by mass or more and 80 parts by mass or less. By defining in such a range, the emulsification stability of the sizing agent can be improved.

The effect of the sizing agent of this embodiment will be described.
(1-1) The sizing agent of the present embodiment is configured to contain the resin (A) and the predetermined fluorine-containing surfactant (B). Therefore, the effect of reducing adhesion spots on inorganic fibers can be improved. In addition, the focusing property of the inorganic fiber treated with the sizing agent can be improved. In addition, the adhesiveness of the inorganic fiber to the base material can be improved.

<Second Embodiment>
Next, a second embodiment that embodies the method for producing an inorganic fiber according to the present invention will be described. With respect to the second embodiment, the same configuration as that of the first embodiment is applied except for the following description.

The method for producing an inorganic fiber of the present embodiment includes a step of adhering the sizing agent of the first embodiment to the carbon fiber. The amount of adhesion (without solvent) is not particularly limited, but it is preferable that the inorganic fiber is adhered to the inorganic fiber so as to be 0.01% by mass or more and 10% by mass or less as a sizing agent. By defining the value within such a numerical range, it is possible to further improve the effect of reducing adhesion spots on inorganic fibers, the effect of focusing, and the like.

(Inorganic fiber)
The type of inorganic fiber applied in this embodiment is not particularly limited, and examples thereof include glass fiber, carbon fiber, ceramic fiber, metal fiber, mineral fiber, rock fiber, and slug fiber. Among these, glass fiber and carbon fiber are preferable from the viewpoint of more effectively exhibiting the effect of the present invention. Examples of the types of carbon fibers include PAN-based carbon fibers obtained from acrylic fibers, pitch-based carbon fibers obtained from pitch as a raw material, recycled carbon fibers, polyester fibers, polyethylene resins, phenol resins, cellulose resins, and lignin. Examples thereof include carbon fibers obtained from a resin or the like as a raw material. In the present invention, the filter medium for an air filter in which a binder and a fluorine-based surfactant are attached to the glass fibers constituting the filter medium is excluded.

In order to attach the sizing agent of the first embodiment to the inorganic fiber, a generally industrially used method can be applied. For example, a roller dipping method, a roller contact method, a spray method, a papermaking method and the like can be mentioned. The inorganic fiber to which the sizing agent is attached may be subsequently dried using a known method.

According to the method for producing an inorganic fiber of the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.
(2-1) The method for producing an inorganic fiber of the present embodiment includes a step of adhering a sizing agent containing a resin (A) and a predetermined fluorine-containing surfactant (B) to the carbon fiber. Therefore, the effect of reducing the adhesion spot of the sizing agent on the inorganic fiber is expected, and the sizing agent can be efficiently adhered to the inorganic fiber.

<Third Embodiment>
Next, a third embodiment that embodies the composite material according to the present invention will be described. With respect to the third embodiment, the same configurations as those of the first and second embodiments are applied except for the following description.

A composite material is obtained by impregnating a matrix resin as a base material with an inorganic fiber to which a sizing agent is attached according to the second embodiment. When producing the composite material, the form of the inorganic fiber is not particularly limited, and for example, a form such as a long fiber, a short fiber, or a non-woven fabric can be adopted.

(Matrix resin)
The matrix resin is appropriately selected from known ones according to the purpose, use and the like of the composite material. Specific examples of the matrix resin include epoxy resin, vinyl ester resin, polyamide resin, polyolefin resin, polyurethane resin, polycarbonate resin, polyester resin, PEEK resin, fluororesin, phenoxy resin, phenol resin, BMI resin, polyimide resin, and polyimide. Examples thereof include resin precursors and polyether sulfone resins. Specific examples of the polyolefin resin include polypropylene resin, polyethylene and the like.

The matrix resin may be selected in consideration of the type of resin contained in the sizing agent from the viewpoint of improving adhesiveness, improving recyclability, and the like. When the matrix resin is applied to a composite material of an epoxy resin, the resin in the sizing agent is preferably a combination of at least one selected from an epoxy resin, a polyurethane resin, a polyester resin, a phenoxy resin, and a polyether ester resin. When the matrix resin is applied to a composite material of a polyamide resin, the resin in the sizing agent is preferably a combination of at least one selected from a polyurethane resin, a polyimide resin precursor, and a polyamide resin. When the matrix resin is applied to a composite material of vinyl ester resin, the resin in the sizing agent is preferably a combination of vinyl ester resin. When the matrix resin is applied to a composite material of polypropylene resin, the resin in the sizing agent is preferably a combination of polyolefin resin.

According to the composite material of the present embodiment, the following effects can be obtained.
(3-1) In the composite material of the present embodiment, a sizing agent containing a resin (A) and a predetermined fluorine-containing surfactant (B) is applied. Therefore, due to the excellent adhesiveness between the inorganic fiber and the matrix resin, a fiber-reinforced resin composite material having various properties such as mechanical properties can be obtained.

The above embodiment may be changed as follows. The above embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range.
-The sizing agent of the above embodiment can be prepared as other components such as water or an organic solvent from the viewpoint of maintaining the performance of the sizing agent and improving the imparting property to inorganic fibers within a range that does not impair the effect of the present invention. It does not prevent the addition of smoothing agents, antioxidants, preservatives, etc.

-The field to which the sizing agent of the above embodiment is applied is not particularly limited. For example, it may be applied to a carbon fiber composite material (CFRP) impregnated with a matrix resin, a reinforcing fiber for concrete, or the like.

Hereinafter, examples and the like will be given in order to make the configuration and effects of the present invention more specific, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, "parts" means "parts by mass" and "%" means "% by mass".

Test category 1 (preparation of sizing agent)
The sizing agent of Example 1 is a fluorine-containing surfactant (B-1) shown in Table 1 as a raw material, an epoxy resin (A-1) shown in Table 2 as a resin (A), and a surfactant (C). A random adduct (C-1) of ethylene oxide (34 mol) and propylene oxide (4 mol) of the tristyrene phenol shown in Table 3 was used.

First, a mixture of raw materials other than the fluorine-containing surfactant (B-1) was heated to 100 ° C. to make it uniform. Then, after cooling to 70 ° C. or lower and gradually adding water, a fluorine-containing surfactant (B-1) was added to obtain an aqueous solution of the sizing agent of Example 1 having the content ratio shown in Table 4. Obtained.

The sizing agents of Examples 2 to 16 and Comparative Examples 1 to 5 or the aqueous liquids of the sizing agents are raw materials such as the fluorine-containing surfactant (B) in Table 1, the resin (A) in Table 2, and optionally Table 3. The surfactant (C) was used. Each component was mixed at the content ratio shown in Table 4 to obtain an aqueous solution of a sizing agent or a sizing agent by the preparation methods shown in A to E below.

A: A mixture of raw materials other than the fluorine-containing surfactant (B) was heated to 100 ° C. to make it uniform. Then, the mixture was cooled to 70 ° C. or lower, water was gradually added, and then the fluorine-containing surfactant (B) was added to obtain an aqueous solution of the sizing agent.

B: An aqueous solution of a sizing agent was obtained by mixing an emulsion containing a resin (A) prepared in advance with a surfactant (C) and a fluorine-containing surfactant (B).
C: An aqueous solution of a sizing agent was obtained by mixing an emulsion containing a resin (A) prepared in advance with a fluorine-containing surfactant (B).

D: An aqueous solution of a sizing agent was obtained by mixing a previously prepared emulsion containing the resin (A) with the surfactant (C).
E: Water was gradually added to a mixture of the resin (A) and the surfactant (C) to obtain an aqueous solution of the sizing agent.

F: A sizing agent was obtained by mixing the surfactant (C) and the fluorine-containing surfactant (B).
Table 4 shows the types and contents of the fluorine-containing surfactant (B), the types and contents of the resin (A) as non-volatile components, the types and contents of the surfactant (C), and the method for preparing the sizing agent. It is shown in the "fluorine-containing surfactant (B)" column, the "resin (A)" column, the "surfactant (C)" column, and the "mixing method at the time of production", respectively.

表４に記載する接着性評価に使用したマトリックス樹脂、＊１）～＊３）の詳細は以下のとおりである。

The details of the matrix resins * 1) to * 3) used for the adhesiveness evaluation shown in Table 4 are as follows.

(Matrix resin used for adhesiveness evaluation)
Epoxy resin (trade name: jER828 + triethylenetetramine manufactured by Mitsubishi Chemical Corporation)
Vinyl ester resin (Showa Denko product name: Lipoxy R-804B (using the company's methyl ethyl ketone peroxide curing agent))
Polyamide resin (UBE nylon 1011FB manufactured by Ube Kosan Co., Ltd.)
Polypropylene resin: 2% maleic anhydride-modified polypropylene * 1) Content ratio of resin (A) to 100 parts of non-volatile content (parts)
* 2) Content ratio (ppm) of the fluorine-containing surfactant (B) in the non-volatile content of the sizing agent
* 3) Non-volatile content standard The non-volatile content was determined as the mass of the absolute dry matter from which the object was heat-treated at 105 ° C. for 2 hours to sufficiently remove volatile substances.

Test category 2 (evaluation of adhesiveness)
Adhesiveness was evaluated by stress measured by the microdroplet method using a commercially available composite interface characterization device. FIG. 1 shows a schematic view of the composite material interface characteristic evaluation device 10.

The aqueous solution or sizing agent of each example prepared as described above was further diluted with water to prepare an aqueous solution having a solid content of 2%. A strand-shaped carbon fiber or glass fiber to which the sizing agent of each example was applied was prepared by supplying oil to the strand-shaped carbon fiber or glass fiber by a dipping method so that this aqueous solution was imparted to the strand-shaped carbon fiber or glass fiber as a solid content of 2%. ..

Next, one carbon fiber or glass fiber was taken out from the carbon fiber or glass fiber, and both ends of the fiber 12 were fixed to the plate-shaped square frame-shaped holder 11 with an adhesive 14 in a tense state. Next, the matrix resin of each example shown in Table 4 was attached to and fixed to the fiber 12 so as to form a resin droplet 13 having a diameter of about 70 μm.

Two plate-shaped blades 17 and 18 whose vertical cross sections are tapered on one side surface are attached to the main body of the apparatus (not shown) in a position where the tip portions 17a and 18a face each other.

The holder 11 was attached to the substrate 16 fixed to the main body of the apparatus at a position where the fiber 12 to which the resin droplet 13 was fixed was sandwiched between the tips 17a and 18a of the two blades 17 and 18. A load cell 15 is connected to the substrate 16, and the stress applied to the substrate 16 is measured.

When the holder 11 is moved in the fiber axial direction at a speed of 5 mm / min, the maximum stress F generated when the resin droplet 13 is separated from the fiber 12 by the tips 17a and 18a of the blades 17 and 18 is applied by the load cell 15. I measured it.

Using the measured values, the interfacial shear strength τ was calculated by the following equation 1. The same operation was performed 20 times, and the average value of the obtained interfacial shear strength was obtained. Further, with respect to the obtained average value, the rate of increase with respect to the reference value of the matrix resin used shown below was obtained and evaluated according to the following criteria. The results are shown in "Adhesion" in Table 4. The types of inorganic fibers used and the types of matrix resin are shown in the "Inorganic fiber used for adhesiveness evaluation" column and the "Matrix resin used for adhesiveness evaluation" column, respectively, in Table 4.

数１において、
Ｆ：繊維１２から樹脂滴１３が剥離する際に生じる最大応力（Ｎ）、
Ｄ：繊維１２の直径（ｍ）、
Ｌ：樹脂滴１３の引き抜き方向の直径（ｍ）。

In number 1,
F: Maximum stress (N) generated when the resin droplet 13 is separated from the fiber 12,
D: Diameter (m) of fiber 12,
L: Diameter (m) of the resin droplet 13 in the drawing direction.

-Standard value of the matrix resin used Epoxy resin: 60 MPa
Vinyl ester resin: 40 MPa
Polyamide resin: 50 MPa
Polypropylene resin: 22MPa
・ Evaluation criteria for adhesiveness ◎ ◎ (excellent): increase rate is 12% or more ◎ (good): increase rate is 9% or more and less than 12% ○ (possible): increase rate is 1% or more and less than 9% × (impossible) : Increase rate is less than 1% Test category 3 (evaluation of adhesion spot suppression)
For the strand-shaped carbon fibers to which the sizing agent was applied obtained in Test Category 2, 5 mg of carbon fibers were sampled at 10 locations every 1 m from a sufficiently dried carbon fiber bundle. The difference between the initial mass and the final mass when the temperature is raised from 40 ° C to 500 ° C at 10 ° C / min by simultaneous measurement of thermal weight and differential thermal (TG-DTA) and kept at 500 ° C for 10 minutes is the amount of sizing agent attached. And said. The standard deviation values of the measured values at 10 points were evaluated according to the following criteria. The results are shown in the "Desmosome suppression" column of Table 4.

・ Evaluation criteria for suppression of adhesion spots ◎ (Good): Less than 0.2 ○ (Yes): 0.2 or more and less than 0.3 × (No): 0.3 or more Test category 4 (Evaluation of cohesiveness)
The strand-shaped carbon fiber to which the sizing agent was applied obtained in Test Category 2 was visually evaluated for the cohesiveness of the yarn at the metal roller portion after the drying step according to the following criteria. The results are shown in the "Focusability" column of Table 4.

・ Evaluation criteria for focusing ○ (possible): When the threads are bundled and passed through the metal roller and there is no problem in processability × (impossible): The threads are not bundled and wrap around the metal roller. If so, as is clear from the results in Table 4, the inorganic fibers to which the sizing agent of each example was applied were more than acceptable in both evaluation of adhesion spot suppression and cohesiveness. In addition, the evaluation of the adhesiveness of the inorganic fiber to which the sizing agent was applied to the matrix resin was more than acceptable. According to the present invention, there is an effect that adhesion spot suppression, focusing property, and adhesiveness can be improved.

10 ... Composite interface characteristic evaluation device 11 ... Holder 12 ... Fiber 13 ... Resin droplet 14 ... Adhesive 15 ... Load cell 16 ... Substrate 17, 18 ... Blade

Claims (13)

A sizing agent for inorganic fibers, which comprises a resin (A) and the following fluorine-containing surfactant (B).
Fluorine-containing surfactant (B): A surfactant having a perfluoroalkenyl group in the molecule. The sizing agent for inorganic fibers according to claim 1, wherein the content ratio of the fluorine-containing surfactant (B) in the non-volatile content of the sizing agent for inorganic fibers is 10 ppm or more and 60,000 ppm or less. The sizing agent for inorganic fibers according to claim 1 or 2, wherein the fluorine-containing surfactant (B) contains a polyoxyalkylene perfluoroalkenyl ether. The resin (A) is an epoxy resin, vinyl ester resin, polyamide resin, polyolefin resin, polyurethane resin, polycarbonate resin, polyester resin, PEEK resin, fluororesin, phenoxy resin, phenol resin, BMI resin, polyimide resin, polyimide resin precursor. The sizing agent for an inorganic fiber according to any one of claims 1 to 3, which contains at least one selected from a body, a polyether sulfone resin, and a polyether ester resin. 3. The sizing agent for inorganic fibers according to any one of the above. The sizing agent for inorganic fibers according to any one of claims 1 to 4, further comprising a surfactant (C) (excluding those corresponding to the fluorine-containing surfactant (B)). Assuming that the total content of the non-volatile content of the resin (A) and the surfactant (C) is 100 parts by mass, the non-volatile content of the resin (A) is 20 parts by mass or more and 99 parts by mass or less and the surfactant. The sizing agent for inorganic fibers according to claim 6, which contains (C) in a proportion of 1 part by mass or more and 80 parts by mass or less. An inorganic fiber (a binder and a fluorine-based surfactant are attached to a glass fiber constituting a filter medium) to which the sizing agent for inorganic fibers according to any one of claims 1 to 7 is attached. Excluding filter media for air filters) . A method for producing an inorganic fiber, which comprises a step of adhering the sizing agent for an inorganic fiber according to any one of claims 1 to 7 to the inorganic fiber. The composite material containing the inorganic fiber and the matrix resin according to claim 8, wherein the resin in the sizing agent for the inorganic fiber is selected from an epoxy resin, a polyurethane resin, a polyester resin, a phenoxy resin, and a polyether ester resin. A composite material comprising at least one of the above, wherein the matrix resin is an epoxy resin. The composite material containing the inorganic fiber and the matrix resin according to claim 8, wherein the resin in the sizing agent for the inorganic fiber contains at least one selected from a polyurethane resin, a polyimide resin precursor, and a polyamide resin. A composite material characterized in that the matrix resin is a polyamide resin. The composite material containing the inorganic fiber and the matrix resin according to claim 8, wherein the resin in the sizing agent for the inorganic fiber contains a vinyl ester resin, and the matrix resin is a vinyl ester resin. Composite material. The composite material containing the inorganic fiber and the matrix resin according to claim 8, wherein the resin in the sizing agent for the inorganic fiber contains a polyolefin resin, and the matrix resin is a polypropylene resin. ..

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