KR20150036577A - Sizing agent for reinforcing fibers, and use thereof - Google Patents

Abstract

An object of the present invention is to provide a reinforcing fiber sizing agent capable of imparting excellent adhesiveness to a matrix resin with respect to reinforcing fibers used for reinforcing a matrix resin. The reinforcing fiber sizing agent of the present invention essentially contains an aromatic polyester-based urethane resin obtained by reacting an organic polyisocyanate compound (A) and an active hydrogen group-containing compound (B), and the active hydrogen group- The aromatic polyester polyol (B1), the active hydrogen group-containing compound (B2) having a carboxyl group and the active hydrogen group-containing compound (B3) having three or more functional groups are included.

Description

[0001] SIZING AGENT FOR REINFORCING FIBERS, AND USE THEREOF [0002]

The present invention relates to reinforcing fiber sizing agents and uses thereof. More particularly, the present invention relates to a reinforcing fiber sizing agent used for reinforcing a matrix resin, a reinforcing fiber strand using the same, and a fiber reinforced composite material.

Fiber reinforced composite materials reinforced with various synthetic fibers are widely used as plastic materials (called matrix resins) for automobile applications, aerospace applications, sports and leisure applications, and general industrial applications. Examples of the fibers used in these composite materials include various inorganic fibers such as carbon fiber, glass fiber and ceramic fiber, and various organic fibers such as aramid fiber, polyamide fiber and polyethylene fiber. These various synthetic fibers are usually formed into a filament shape and then processed into a sheet-like intermediate material called a one-way prepreg by a hot-melt method, a drum winding method, or the like, processed by a filament winding method, Or it is processed into a short fiber shape or the like, and is used as reinforcing fiber through various high-grade processing steps.

Among the above-mentioned matrix resins, polyolefin resins, polyamide resins, polycarbonate resins, polyacetal resins, ABS resins, polyphenylene sulfide resins, polyetherimide resins and the like, which are attracting attention because they are easy to mold and are also advantageous in terms of recycling In the case of a so-called fiber-reinforced composite material using a thermoplastic resin, the reinforcing fiber is often used in a short fiber shape cut to a length of 1 to 15 mm. When the pellets obtained by kneading the short fibers and the thermoplastic resin are produced, the aggregation property of the short fibers is important. If the pellets are inadequate, destabilization of the short fiber supply amount, strand pieces and the like are generated, and the physical properties of the resultant composite material may be deteriorated . In order to prevent this, a number of techniques for imparting a sizing agent containing various thermoplastic resins as a main agent have been proposed (refer to Patent Document 1) and widely used industrially have.

However, in the application of the sizing agent described in the prior art, the adhesiveness between the matrix resin and the reinforcing fiber is insufficient, the properties of the resulting composite material may not be reached, and the adhesiveness can be further improved I was desperately demanding sizing.

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-131959

SUMMARY OF THE INVENTION In view of the background of the prior art, it is an object of the present invention to provide a reinforcing fiber sizing agent capable of imparting excellent adhesion with a matrix resin to reinforcing fibers used for reinforcing a matrix resin, Strand and fiber reinforced composite material.

DISCLOSURE OF THE INVENTION The inventors of the present invention have made intensive investigations in order to solve the above problems and have found that the use of a reinforcing fiber sizing agent containing a specific aromatic polyester-based urethane resin significantly improves the adhesiveness and reached the present invention .

That is, the reinforcing sizing sizing agent of the present invention essentially contains an aromatic polyester-based urethane resin, and the aromatic polyester-based urethane resin is obtained by reacting the organic polyisocyanate compound (A) and the active hydrogen group- containing compound (B) , And the active hydrogen group-containing compound (B) includes an aromatic polyester polyol (B1), an active hydrogen group-containing compound (B2) having a carboxyl group and an active hydrogen group-containing compound (B3) .

The active hydrogen group ratio of the aromatic polyester polyol (B1) is preferably 5 to 80 mol% when the active hydrogen group ratio of the active hydrogen group-containing compound (B) as a whole is 100 mol%. Likewise, the active hydrogen group-containing compound (B2) having a carboxyl group preferably has an active hydrogen group content of 5 to 60 mol%. Likewise, the active hydrogen group ratio of the trifunctional or more active hydrogen group-containing compound (B3) is preferably 5 to 70 mol%.

The active hydrogen group-containing compound (B) preferably further comprises a polyalkylene glycol (B4) having a weight average molecular weight of 100 to 2000. When the active hydrogen group ratio of the active hydrogen group-containing compound (B) as a whole is 100 mol%, the active hydrogen group ratio of the polyalkylene glycol (B4) is preferably 10 to 40 mol%.

The reinforcing fiber sizing agent of the present invention may also be expressed as follows. That is, the reinforcing sizing agent sizing agent of the present invention comprises an aromatic polyester-based urethane resin as essential components, wherein the aromatic polyester-based urethane resin contains the structural unit (a) derived from the organic polyisocyanate compound (A) (B1) derived from an aromatic polyester polyol (B1), an active hydrogen group-containing compound (B2) having a carboxyl group and a structural unit (b) derived from an aromatic polyester polyol (B1) (B3) derived from the trifunctional or more active hydrogen group-containing compound (B3).

The proportion of the constituent unit (b1) in the entire constituent unit (b) is preferably 5 to 80 mol%. Similarly, the proportion of the constituent unit (b2) is preferably 5 to 60 mol%. The proportion of the constituent unit (b3) is preferably 2 to 70 mol%.

The structural unit (b) preferably further comprises a structural unit (b4) derived from a polyalkylene glycol (B4) having a weight average molecular weight of 100 to 2000. The proportion of the constituent unit (b4) in the total of the constituent unit (b) is preferably 10 to 40 mol%.

The glass transition point of the aromatic polyester-based urethane resin is preferably 40 캜 or lower.

The dynamic surface tension when water is added and the non-volatile content of the sizing agent is 2% by weight is 40 to 70 mN / m when measured under the condition of generating one foam at 100 milliseconds according to the maximum vapor pressure method desirable.

The active hydrogen group-containing compound (B2) having a carboxyl group is preferably at least one member selected from 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid.

The active hydrogen group-containing compound (B3) having three or more functional groups is preferably at least one member selected from trimethylolethane, trimethylolpropane and pentaerythritol.

The reinforcing sizing agent sizing agent of the present invention preferably further contains an ester compound (C) having at least one terminal of the compound main chain having a vinyl ester group, an acrylate group or a methacrylate group.

The reinforcement sizing agent of the present invention preferably further contains a polyoxyalkylene alkyl ether (D) which is an alkylene oxide adduct of a monovalent alcohol having 4 to 14 carbon atoms.

When the nonvolatile content of the reinforcing fiber sizing agent is raised to 300 ° C, the weight reduction ratio of the nonvolatile matter is preferably 15% by weight or less.

The reinforcing fiber strand of the present invention is obtained by adhering the reinforcing fiber sizing agent to the raw reinforcing fiber strand.

The raw material reinforcing fiber strand is preferably a raw carbon fiber strand.

The fiber-reinforced composite material of the present invention comprises a matrix resin and the reinforcing fiber strand. The matrix resin is preferably a thermoplastic resin.

The reinforcing fiber sizing agent of the present invention can impart excellent adhesion with the matrix resin to the reinforcing fiber. The reinforcing fiber strand of the present invention has excellent adhesion with a matrix resin. By using the reinforcing fiber strand of the present invention, a fiber reinforced composite material having excellent physical properties can be obtained.

INDUSTRIAL APPLICABILITY The present invention essentially encompasses a specific aromatic polyester-based urethane resin as a reinforcing fiber sizing agent used for reinforcing a matrix resin. This will be described in detail below.

[Aromatic polyester-based urethane resin]

The aromatic polyester-based urethane resin, which is an essential component of the sizing agent of the present invention, is a polymer component obtained by subjecting an organic polyisocyanate compound (A) and an active hydrogen group-containing compound (B) The active hydrogen group-containing compound (B) comprises an aromatic polyester polyol (B1), an active hydrogen group-containing compound (B2) having a carboxyl group and an active hydrogen group-containing compound (B3) having three or more functional groups. By using such a specific aromatic polyester-based urethane resin as a reinforcing fiber useful sizing agent, adhesion between the reinforcing fiber and the matrix resin can be remarkably improved.

The organic polyisocyanate compound (A) is an essential component of the aromatic polyester-based urethane resin and contains at least two (preferably 2 to 6, more preferably 2 to 3, more preferably 2) Of an isocyanate group. The organic polyisocyanate compound (A) may be used alone or in combination of two or more.

Examples of the organic polyisocyanate compound (A) include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates.

Examples of the aliphatic polyisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4- Diisocyanate ethyl caproate, bis (2-isocyanate ethyl) fumarate, and bis (2-isocyanatoethyl) fumarate. -Isocyanatoethyl) carbonate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate and lysine ester triisocyanate For example, the reaction product of lysine and alkanolamine Phosgene cargo, and the like can be mentioned 2-isocyanate ethyl-2,6-diisocyanate hexanoate, and 2-or 3-isocyanate propyl-2,6-diisocyanate hexanoate), trifunctional or higher polyisocyanate and the like.

Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis Diisocyanate such as 2-isocyanatoethyl) -4-cyclohexylene-1,2-dicarboxylate and 2,5- or 2,6-norbornene diisocyanate; trifunctional or higher functional polyisocyanate such as bicycloheptane triisocyanate And the like.

Examples of the aromatic polyisocyanate include 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, 2,4- Diisocyanate, phenylene diisocyanate, xylene diisocyanate, tetramethylxylylene diisocyanate, and the like can be used. Specific examples of the polyisocyanate include polyisocyanate, polyisocyanate, polyisocyanate, polyisocyanate, have.

Among them, an aliphatic polyisocyanate and an alicyclic polyisocyanate are preferable, and aliphatic polyisocyanate is more preferable, and an aliphatic polyisocyanate such as ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, Isocyanate and dodecamethylene diisocyanate are more preferable, and hexamethylene diisocyanate is particularly preferable.

The active hydrogen group-containing compound (B) means an essential component of the aromatic polyester-based urethane resin and contains at least one active hydrogen group in the molecule. Active hydrogen groups refer to active groups, including hydrogen, that can react with isocyanate groups. Examples of the active hydrogen group include a hydroxyl group, an amino group, a carboxyl group, and a thiol group.

The active hydrogen group-containing compound (B) comprises the following aromatic polyester polyol (B1), an active hydrogen group-containing compound (B2) having a carboxyl group and an active hydrogen group-containing compound (B3) having three or more functional groups. In addition, other active hydrogen group-containing compounds than the above may be included within the range not impairing the effect of the present invention.

The aromatic polyester polyol (B1) is a copolymer of a polycarboxylic acid or an anhydride thereof and a polyol, wherein at least one of the polycarboxylic acid or its anhydride and the polyol contains an aromatic compound. The aromatic polyester polyol (B1) is composed of a polyol at its terminal and has at least two active hydrogen groups in the molecule. The number of active hydrogen groups is preferably 2 to 4, and more preferably 2. The aromatic polyester polyol (B1) may be used alone or in combination of two or more.

Thus, by making the aromatic polyester polyol (B1) and other essential active hydrogen group-containing compounds as essential constituents of the aromatic polyester-based urethane resin, the adhesion between the reinforcing fiber and the matrix resin can be remarkably improved. Further, when an aliphatic polyester polyol having no aromatic compound in the molecule is used in place of the aromatic polyester polyol (B1), the adhesiveness is hardly improved and the heat resistance is also low.

Examples of the polycarboxylic acids include aromatic dicarboxylic acids, sulfonic acid salt-containing aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and trifunctional or higher functional polycarboxylic acids.

Examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, .

Examples of the sulfonate salt-containing aromatic dicarboxylic acid include sulfoterephthalic acid salt and 5-sulfoisophthalic acid salt.

Examples of the aliphatic dicarboxylic acid or alicyclic dicarboxylic acid include fumaric acid, maleic acid, itaconic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dimeric acid, 1,4-cyclohexanedicarboxylic acid, And the like.

Examples of polycarboxylic acids having three or more functional groups include trimellitic acid, pyromellitic acid, trimellitic anhydride, and pyromellitic anhydride.

Examples of the polyol include a diol and a polyol having three or more functional groups.

Examples of diols include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, polybutylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, tetra Methylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, resorcin, hydroquinone, bisphenol A or an alkylene oxide adduct thereof.

Examples of polyols having three or more functional groups include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, ditrimethylolpropane, and the like.

Among them, a combination of an aromatic dicarboxylic acid and a diol is preferable as the aromatic polyester polyol (B1), and a combination of terephthalic acid and / or isophthalic acid as an aromatic dicarboxylic acid and ethylene glycol and / or neopentyl glycol as a diol desirable.

The hydroxyl value of the aromatic polyester polyol (B1) is preferably 10 to 250 mgKOH / g, more preferably 15 to 150 mgKOH / g, and still more preferably 30 to 120 mgKOH / g. The hydroxyl group value was measured in accordance with JIS K 1557-1970.

The number average molecular weight of the aromatic polyester polyol (B1) is preferably from 500 to 10000, more preferably from 700 to 8000, and even more preferably from 1000 to 4000. The number average molecular weight in the present invention is calculated from the hydroxyl value.

The aromatic polyester polyol (B1) can be obtained by the same method as the known polyester production method by dehydrating and condensing the above polycarboxylic acid or its anhydride with the polyol.

The active hydrogen group-containing compound (B2) having a carboxyl group means a compound having at least one carboxyl group and at least one active hydrogen group in the molecule. By using the active hydrogen group-containing compound (B2) having a carboxyl group as an essential constituent, the aromatic polyester-based urethane resin can be imparted with water dispersing ability. The number of active hydrogen groups is preferably from 1 to 4, more preferably from 2 to 3. The active hydrogen group-containing compound (B2) having a carboxyl group may be used alone or in combination of two or more.

Examples of the active hydrogen group-containing compound (B2) having a carboxyl group include a polyol having a carboxyl group and a monool having a carboxyl group.

Examples of the polyol having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolpentanoic acid, 2,2- dimethylolheptanoic acid, dioxymaleic acid, 2,6- Benzoic acid and the like.

Examples of the monool having a carboxyl group include glycolic acid, lactic acid, hydroxybutyric acid, salicylic acid, parahydroxybenzoic acid, and cumaric acid.

Among these, from the viewpoint of high molecular weight, the active hydrogen group-containing compound (B2) having a carboxyl group is preferably a polyol having a carboxyl group, more preferably 2,2-dimethylolpropionic acid or 2,2- 2,2-dimethylolpropionic acid is more preferable.

The trifunctional or more active hydrogen group-containing compound (B3) refers to a compound containing at least three active hydrogen groups in the molecule. The trifunctional or more active hydrogen group-containing compound (B3) refers to a compound excluding the aromatic polyester polyol (B1) and the active hydrogen group-containing compound (B2) having a carboxyl group. The number of active hydrogen groups is preferably from 3 to 8, more preferably from 3 to 4. Examples of the trifunctional or higher active hydrogen group-containing compound (B3) include polyols having three or more active hydrogen groups and polyamines having three or more functional groups.

Examples of polyfunctional or higher functional polyols include trimethylol ethane, trimethylol propane, glycerin, sorbitol, pentaerythritol, ditrimethylol propane, and the like. Examples of trifunctional or higher polyamines include melamine, diethylenetriamine, triethylenetetramine, tri (aminomethyl) propane, and the like. Among them, trimethylolpropane, pentaerythritol and ditrimethylolpropane are preferable from the viewpoint of adhesiveness, and trimethylolpropane and pentaerythritol are more preferable.

The active hydrogen group-containing compound (B) preferably further comprises a polyalkylene glycol (B4) having a weight average molecular weight of 100 to 2000. By using the polyalkylene glycol (B4), the sizing agent has excellent film flexibility and uniform adhesion. The weight average molecular weight in the present invention refers to a value measured in accordance with the gel permeation chromatography (GPC) measurement method under the following measurement conditions and converted to polystyrene.

(GPC measurement conditions)

Apparatus: " HPLC LC-6A SYSTEM " (manufactured by SHIMAZU)

KF-801 (300 mm x 8 mm?), KF-802.5 (300 mm x 8 mm?), KF-801 Mm x 8 mm?) "(Manufactured by SHODEX Co., Ltd.)

Mobile phase: tetrahydrofuran (THF)

Flow rate: 1.0 ml / min

Sample volume: 100 쨉 l (100-fold dilution)

Column temperature: 50 ° C

Calibration curve standard material: polystyrene (PSt)

The weight average molecular weight of the polyalkylene glycol (B4) is preferably 100 to 2,000, more preferably 150 to 1,500, and even more preferably 200 to 1,000. If the molecular weight is less than 100, the film flexibility may be insufficient. On the other hand, when the molecular weight exceeds 2000, the adhesiveness may be lowered.

Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, polyethylene glycol / polypropylene glycol block copolymer, and polyethylene glycol / polypropylene glycol random copolymer. Alternatively, it may be blocked with an alkyl group, an aromatic group or the like so that only one terminal is a hydroxyl group.

Among these, polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol are preferable, and polyethylene glycol and polytetramethylene glycol are more preferable.

The active hydrogen group-containing compound (B) may contain an active hydrogen group-containing compound other than the above insofar as the effects of the present invention are not impaired. Other active hydrogen group-containing compounds (B5) include diols and the like.

Examples of diols include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, polybutylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, tetra Methylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, resorcin, hydroquinone, bisphenol A or an alkylene oxide adduct thereof.

The proportion of active hydrogen groups in the aromatic polyester polyol (B1) is preferably from 5 to 80 mol%, more preferably from 10 to 70 mol%, and more preferably from 10 to 70 mol%, based on the total amount of the active hydrogen groups in the active hydrogen group- , And more preferably from 15 to 50 mol%. If the proportion is less than 5 mol%, both the adhesiveness and the heat resistance may be insufficient. On the other hand, if the ratio exceeds 80 mol%, the water-soluble resin may become difficult to be water-soluble.

Likewise, the active hydrogen group ratio of the active hydrogen group-containing compound (B2) having a carboxyl group is preferably from 5 to 60 mol%, more preferably from 15 to 50 mol%, still more preferably from 20 to 40 mol%. When the ratio is less than 5 mol%, the water-soluble resin may become difficult to be water-soluble. On the other hand, when the proportion exceeds 60 mol%, the hygroscopicity may be increased or the heat resistance may be insufficient.

Likewise, the active hydrogen group ratio of the trifunctional or more active hydrogen group-containing compound (B3) is preferably from 5 to 70 mol%, more preferably from 10 to 60 mol%, still more preferably from 15 to 50 mol%. When the proportion is less than 5 mol%, the adhesiveness may be insufficient. On the other hand, when the ratio exceeds 70 mol%, the reaction control becomes difficult and the synthesis becomes impossible in some cases.

When the active hydrogen group of the aromatic polyester polyol (B1) and the active hydrogen group of the active hydrogen group-containing compound (B2) having a carboxyl group, Group and the active hydrogen group of the trifunctional or more active hydrogen group-containing compound (B3) is preferably 40 mol% or more, more preferably 50 mol% or more, and still more preferably 60 mol% or more. If the ratio is less than 40 mol%, good adhesion and heat resistance may not be obtained at the same time.

When the active hydrogen group-containing compound (B) further contains the polyalkylene glycol (B4), when the active hydrogen group ratio of the active hydrogen group-containing compound (B) as a whole is 100 mol%, the polyalkylene glycol B4) is preferably from 15 to 40 mol%, more preferably from 20 to 40 mol%, still more preferably from 20 to 30 mol%. When the proportion is more than 40 mol%, both the adhesiveness and the heat resistance may become insufficient.

The active hydrogen group of the aromatic polyester polyol (B1), the active hydrogen group of the active hydrogen group-containing compound (B2) having a carboxyl group, the active hydrogen group of the aromatic polyester polyol (B1) The ratio of the active hydrogen group of the trifunctional or more active hydrogen group-containing compound (B3) to the active hydrogen group sum of the polyalkylene glycol (B4) is preferably at least 60 mol%, more preferably at least 70 mol% % Or more.

When the active hydrogen group-containing compound (B) contains other active hydrogen group-containing compound (B5), the active hydrogen group-containing compound (B) The active hydrogen group ratio of the group-containing compound (B5) is preferably 2 to 40 mol%, more preferably 5 to 30 mol%, and still more preferably 10 to 20 mol%. If the ratio exceeds 40 mol%, good adhesion may not be obtained.

The molar ratio (isocyanate group / active hydrogen group) of the isocyanate group of the organic polyisocyanate compound (A) and the active hydrogen group of the active hydrogen group-containing compound (B) is preferably from 40/60 to 55/45, 48, and more preferably 45/55 to 50/50.

The aromatic polyester-based urethane resin is an aromatic polyester-based urethane resin composed of a constituent unit (a) derived from an organic polyisocyanate compound (A) and a constituent unit (b) derived from an active hydrogen group- Based urethane resin. The constituent unit (b) is a constituent unit derived from a constituent unit (b1) derived from an aromatic polyester polyol (B1), a constituent unit (b2) derived from an active hydrogen group containing compound (B2) having a carboxyl group, (B3) derived from the structural unit (B3). Details of the organic polyisocyanate compound (A), active hydrogen group containing compound (B), aromatic polyester polyol (B1), active hydrogen group containing compound (B2) having a carboxyl group and active hydrogen group containing compound (B3) As described above.

Herein, the structural unit (a) derived from the organic polyisocyanate compound (A) refers to a unit constituted of the organic polyisocyanate compound (A) as a raw material, and includes up to the structure of "-NHC (= O) -" . On the other hand, the structural unit (b) derived from the active hydrogen group-containing compound (B) refers to a unit composed of the active hydrogen group-containing compound (B) as a raw material, It says the rest.

The proportion of the constituent unit (b1) in the entire constituent unit (b) is preferably 5 to 80 mol%, more preferably 10 to 70 mol%, and still more preferably 15 to 50 mol%. If the proportion is less than 5 mol%, both the adhesiveness and the heat resistance may be insufficient. On the other hand, when the ratio is more than 90 mol%, it may become difficult to achieve water-solubility.

The proportion of the constituent unit (b2) in the entire constituent unit (b) is preferably 5 to 60 mol%, more preferably 15 to 50 mol%, and still more preferably 20 to 40 mol%. When the ratio is less than 5 mol%, the water-soluble resin may become difficult to be water-soluble. On the other hand, when the proportion exceeds 70 mol%, the hygroscopicity may be increased or the heat resistance may be insufficient.

The proportion of the constituent unit (b3) in the entire constituent unit (b) is preferably 2 to 70 mol%, more preferably 5 to 60 mol%, and still more preferably 10 to 40 mol%. When the proportion is less than 5 mol%, the adhesiveness may be insufficient. On the other hand, when the ratio exceeds 80 mol%, the reaction control becomes difficult and the synthesis may become impossible.

The total proportion of the constituent unit (b1), the constituent unit (b2) and the constituent unit (b3) in the entire constituent unit (b) is preferably at least 40 mol%, more preferably at least 50 mol% % Or more. If the ratio is less than 40 mol%, good adhesion and heat resistance may not be obtained at the same time.

The structural unit (b) preferably contains a structural unit (b4) derived from a polyalkylene glycol (B4) having a weight average molecular weight of 100 to 2000. By including the polyalkylene glycol (B4), film flexibility can be imparted. Details of the polyalkylene glycol (B4) are as described above.

When the structural unit (b4) is further included, the proportion of the structural unit (b4) in the entire structural unit (b) is preferably 10 to 40 mol%, more preferably 15 to 35 mol% Mol% is more preferable. When the proportion is more than 40 mol%, both the adhesiveness and the heat resistance may become insufficient.

The proportion of the total of the constituent unit (b1), the constituent unit (b2), the constituent unit (b3) and the constituent unit (b4) in the entire constituent unit (b) at that time is preferably 60 mol% Or more, and more preferably 80 mol% or more.

When the structural unit (b) contains the structural unit (b5) derived from the other active hydrogen group-containing compound (B5), the proportion of the structural unit (b5) , More preferably 5 to 30 mol%, and still more preferably 10 to 20 mol%. If the ratio exceeds 40 mol%, good adhesion may not be obtained.

The molar ratio of the constituent unit (a) to the constituent unit (b) is preferably 40/60 to 55/45, more preferably 45/55 to 55/45, and even more preferably 48/50 to 50/50.

In addition, when the aromatic polyester-based urethane resin is emulsified and dispersed in water and used, it is preferable that the active hydrogen group-containing compound (B2) having a carboxyl group is introduced from the point of view of not requiring the addition of an emulsifier component such as a surfactant It is preferable to partially or wholly neutralize the resulting carboxyl group with a basic component.

Examples of the basic component include inorganic bases such as sodium hydroxide and potassium hydroxide, organic bases such as monopropylamine, monobutylamine, diethylamine, triethylamine, tributylamine, monoethanolamine, monocyclohexylamine, diethanolamine, Amines such as dimethylethanolamine, ammonia, and the like. Among these, amines are preferable, and monoethanolamine, diethanolamine, triethanolamine and dimethylethanolamine are more preferable.

The weight average molecular weight of the aromatic polyester-based urethane resin used in the present invention is preferably 5,000 to 200,000, more preferably 8,000 to 100,000, and even more preferably 10,000 to 700,000. If the molecular weight is less than 4,000, good adhesiveness and heat resistance may not be obtained at the same time. On the other hand, when the molecular weight exceeds 300,000, it may be difficult to disperse in water.

When the aromatic polyester-based urethane resin used in the present invention is measured by a differential scanning calorimeter (DSC), the glass transition point is preferably 40 ° C or lower, more preferably -25 ° C to 30 ° C, more preferably -15 ° C to 25 ° C desirable. When the glass transition point is 40 占 폚 or less, the mobility of the polymer molecules at the time of forming the composite material becomes high. Especially when the matrix resin is relatively excellent in adhesion to fibers, such as polyamide, And quickly forms an interfacial layer having superior adhesiveness. As a result, it is considered that the adhesive strength as a composite material is increased.

The term "glass transition point" in the present invention means a straight line extending equidistant from the extended straight line of each standard in the portion showing the stepped shape change of the DSC curve obtained by the DSC measurement described later according to JIS-K7121 And a point at which the curves of the step-shaped change portion cross (in degrees Celsius).

A method for producing the aromatic polyester-based urethane resin is not particularly limited, and a known method can be adopted. For example, a one-shot method in which all the components are simultaneously reacted, or a multistage method in which an active hydrogen group-containing compound (B) is added to the organic polyisocyanate compound (A) in a stepwise manner, or an organic polyisocyanate A prepolymer method in which a compound (A) is reacted with an active hydrogen group-containing compound (B) to synthesize a prepolymer having an isocyanate at the terminal and then a chain elongating agent is reacted may be used.

When preparing the aromatic polyester-based urethane resin of the present invention, an urethane formation catalyst can be used if necessary. Examples of the urethanization catalyst which can be used in the present invention include nitrogen-containing compounds such as triethylamine, triethylenediamine or N-methylmorpholine, metal salts such as potassium acetate, zinc stearate or tin octylate, di And organic metal compounds such as butyl laurate.

[Ester compound (C)]

The sizing agent of the present invention preferably further contains an ester compound (C) having a vinyl ester group, an acrylate group or a methacrylate group on at least one end of the main compound chain. When the reinforcing fibers are processed into one directional sheet or fabric, it is important that the fiber strands are promptly opened by a guide bar of a forming process or the like. However, in the conventional sizing agent, there was. By containing the ester compound (C) in addition to the aromatic polyester-based urethane resin described above, the sizing agent of the present invention can simultaneously impart excellent adhesion and excellent openability to the reinforcing fiber.

The ester compound (C) is a compound having a highly reactive double bond, and any aromatic or aliphatic compound can be selected. The ester compound (C) may be used singly or in combination of two or more kinds. Further, the vinyl ester group represents a group represented by "CH2 = CHOCO-", the acrylate group represents a group represented by "CH2 = CHCOO-", and the methacrylate group represents a group represented by "CH2 = CCH3COO-".

Examples of the ester compound (C) include alkyl (meth) acrylate esters, alkoxypolyalkylene glycol (meth) acrylate esters, benzyl (meth) acrylate esters, phenoxyethyl (meth) acrylate, 2-hydroxyalkyl (Meth) acrylate ester, dialkylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di (Meth) acrylate, glycerin di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, dimethyloltricyclodecane di (Meth) acrylic acid ester, an alkylene oxide adduct of bisphenol A (meth) acrylic acid ester, a bisphenol A diglycidyl ether (meth) acrylic acid adduct, an alkylene oxide adduct of bisphenol A di (Meth) acrylic acid ester, phenoxypolyalkylene glycol (meth) acrylate, glycidyl (meth) acrylate, phenoxyalkyl (meth) acrylate, phenoxypolyalkylene glycol (Meth) acryloyloxyethyl succinate, 2- (meth) acryloyloxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropanol (Meth) acryloyloxyethyl-2-hydroxyethyl-phthalic acid, neopentyl glycol (meth) acrylic acid benzoic acid ester, alkylene oxide added trimethylolpropane tri (meth) acrylate, pentaerythritol tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate hex And the like can be mentioned diisocyanate urethane prepolymer.

Among them, examples of the ester compound (C) include 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di (meth) acrylate, 2- (meth) acryloyloxyethyl phthalic acid, 2- (Meth) acryloyloxyethyl-2-hydroxyethyl-phthalic acid, neopentyl glycol (meth) acrylic acid benzoic acid ester, bisphenol A (meth) acrylic acid ester, alkylene oxide-added bisphenol A (meth) acrylic acid ester, bisphenol A diglycidyl (Meth) acrylic acid adducts, alkylene oxide adducts of bisphenol A diglycidyl ether (meth) acrylic acid adducts, and polyalkylene glycol di (meth) acrylates, bisphenol A (meth) Alkylene oxide adducts bisphenol A (meth) acrylic esters, bisphenol A diglycidyl ether (meth) acrylic acid adducts, alkylene oxide adducts bisphenol A diglycidyl Ether (meth) acrylic acid added is more preferably water.

[Polyoxyalkylene alkyl ether (D)]

The sizing agent of the present invention preferably further contains a polyoxyalkylene alkyl ether (D) which is an alkylene oxide adduct of a monovalent alcohol having 4 to 14 carbon atoms. By containing the polyoxyalkylene alkyl ether (D) in addition to the aromatic polyester-based urethane resin, the sizing agent quickly adheres uniformly to the fiber-to-fiber and the fiber, and has excellent uniform adhesion. Therefore, the reinforcing fiber can be further improved in adhesion. One or more polyoxyalkylene alkyl ethers (D) may be used. The production method of the polyoxyalkylene alkyl ether (D) is not particularly limited, and a known method can be adopted.

The monohydric alcohol having 4 to 14 carbon atoms may be either linear, branched or cyclic (alicyclic or aromatic aliphatic), and may be either saturated or unsaturated. Examples of the straight chain saturated alcohol include butyl alcohol, hexyl alcohol, octyl alcohol, decyl alcohol, lauryl (dodecyl) alcohol, and tetradecyl alcohol. Examples of branched saturated alcohols include 2-ethylhexyl alcohol and the like. Examples of the cyclic alcohols include cyclohexyl alcohol and benzyl alcohol. Of these, straight-chain or branched saturated alcohols having 6 to 12 carbon atoms are preferable, and hexyl alcohol and 2-ethylhexyl alcohol are more preferable from the viewpoint of uniform adhesion.

The alkylene oxide is preferably an alkylene oxide having 2 to 4 carbon atoms. Specifically, there may be mentioned ethylene oxide (hereinafter may be referred to as EO), propylene oxide (hereinafter may be referred to as PO), 1,2-, 1,3-, 2,3- or 1,4-butylene oxide (Hereinafter referred to as " BO "). Two or more kinds of alkylene oxides may be used. Of these, EO and / or PO is preferred from the viewpoint of uniform adhesion. In the case of using two or more kinds of alkylene oxide addition methods, a random addition, a block addition, a combination thereof, and the like can be mentioned, but a block addition and a block addition after random addition are preferable.

The number of moles of the alkylene oxide added is preferably 1 to 12 moles, more preferably 1 to 10 moles, and still more preferably 1 to 8 moles, from the viewpoint of uniform adhesion.

The weight average molecular weight of the D component is preferably 200 to 2000, more preferably 250 to 1800, and even more preferably 280 to 1500.

[Reinforcing fiber useful sizing agent]

The sizing agent of the present invention is a reinforcing fiber useful for reinforcing a matrix resin. The matrix resin is preferably a thermoplastic resin in that the sizing agent of the present invention has a higher effect of improving the adhesiveness.

The sizing agent of the present invention essentially contains the aromatic polyester-based urethane resin described above. The weight ratio of the aromatic polyester-based urethane resin to the nonvolatile matter of the sizing agent is preferably 10% by weight or more, more preferably 20% by weight or more, still more preferably 30% by weight or more, and particularly preferably 50% Do. When the weight ratio is less than 10% by weight, excellent adhesion characteristic of the present compound can not be obtained. The nonvolatile matter in the present invention refers to an absolute drying component when the sizing agent is heat-treated at 105 캜 to remove solvents and the like and reaches a constant weight.

When the sizing agent of the present invention is measured under the condition that the dynamic surface tension when 1% by weight of the nonvolatile matter content of the sizing agent is added by adding water, the foam is generated at 100 milliseconds by the maximum foaming method , And 40 to 70 mN / m.

With this property, in the sizing agent imparting step to the fibers, the sizing agent is uniformly adhered to the inside of the fiber strand quickly, specifically to the fiber-to-fiber interstices and the fiber strands. And, in forming the composite material, the sizing agent layer uniformly adhered to the fiber improves the wettability of the matrix resin with the fibers, thereby improving the physical properties as a composite material.

When the dynamic surface tension exceeds 70 mN / m, the uniform adhesion of the sizing agent to the reinforcing fibers may be deteriorated. On the other hand, when the dynamic surface tension is less than 40 mN / m, it may become difficult to control the amount of the sizing agent applied to the reinforcing fibers. The dynamic surface tension is preferably 40 to 70 mN / m, more preferably 45 to 65 mN / m, and particularly preferably 45 to 60 mN / m.

When the sizing agent of the present invention contains the ester compound (C), the weight ratio (aromatic polyester-based urethane resin / ester compound (C)) of the aromatic polyester-based urethane resin and the ester compound (C) The ratio is preferably 10/90 to 90/10, more preferably 80/20 to 20/80, and even more preferably 30/70 to 70/30 in terms of imparting frictional properties.

The weight ratio of the total amount of the aromatic polyester-based urethane resin and the ester compound (C) in the nonvolatile matter of the sizing agent at that time is preferably 60% by weight or more, more preferably 70 to 99% by weight, more preferably 80 to 98% , And particularly preferably 90 to 97 wt% or more.

The proportion by weight of the aromatic polyester-based urethane resin in the nonvolatile matter of the sizing agent at that time is preferably 10 to 90% by weight, more preferably 20 to 80% by weight, still more preferably 30 to 70% by weight . The weight ratio of the ester compound (C) in the nonvolatile matter of the sizing agent is preferably 10 to 90% by weight, more preferably 20 to 80% by weight, still more preferably 30 to 70% by weight. If the weight ratio of the ester compound (C) is more than 90% by weight, the entanglement between the fibers deteriorates to cause napping, and sufficient strength can not be obtained when the composite material is used.

When the sizing agent of the present invention contains the polyoxyalkylene alkyl ether (D), the weight ratio of the polyoxyalkylene alkyl ether (D) in the nonvolatile matter of the sizing agent is preferably 0.5 to 10% by weight, More preferably 8% by weight, and still more preferably 3% to 5% by weight. When the weight ratio of the polyoxyalkylene alkyl ether (D) is more than 10% by weight, the sizing agent may be drawn on the reinforcing fibers to lower the adhesiveness.

In the sizing agent of the present invention, when the nonvolatile component of the sizing agent is measured by a differential differential thermal balance (TG-DTA), the weight reduction ratio at 300 ° C is preferably 15% by weight or less, more preferably 10% Do. If the weight loss rate at 300 占 폚 exceeds 20% by weight, adhesion of the matrix resin to the reinforcing fibers may be inhibited by the generation of pyrolysis gas of the sizing agent.

The sizing agent of the present invention may contain water from the viewpoints of safety to the human body at the time of handling, prevention of disasters such as fire, prevention of contamination of the natural environment, and the like. An organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone or the like may be used as long as the effect of the present invention is not impaired.

In the sizing agent of the present invention, the aromatic polyester-based urethane resin is formed by self-emulsification and / or emulsion-dispersion of water. The average particle diameter of the aromatic polyester-based urethane resin is not particularly limited, but is preferably 10 占 퐉 or less, more preferably 0.01 to 1 占 퐉, and still more preferably 0.01 to 0.5 占 퐉. If the average particle diameter exceeds 10 탆, it is not possible to uniformly adhere to the reinforcing fibers, and the sizing agent itself may be separated in a few days, which may result in poor storage stability and impracticality.

The average particle diameter referred to in the present invention refers to an average value calculated from the particle size distribution measured with a laser diffraction / scattering type particle size distribution analyzer (Horiba LA-910).

The sizing agent of the present invention may contain other components than the above-described aromatic polyester-based urethane resin within the range not impairing the effect of the present invention. Examples of the other components include various surfactants, various smoothing agents, antioxidants, flame retardants, antibacterial agents, crystal nucleating agents and antifoaming agents, and they may be used alone or in combination of two or more.

When the surfactant contains a water-insoluble or water-insoluble resin in the aromatic polyester-based urethane resin or other sizing agent, the surfactant can be used as an emulsifier to efficiently perform aqueous-based emulsification.

The surfactant is not particularly limited, and known ones can be appropriately selected from nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants. The surfactant may be used alone or in combination of two or more.

Examples of the nonionic surfactant include alkylene oxide-added nonionic surfactants such as higher alcohols, higher fatty acids, alkylphenols, styrenated phenols, benzylphenols, sorbitan, sorbitan esters, castor oil, (In which two or more kinds of alkylene oxides such as ethylene oxide and propylene oxide are added), a polyalkylene glycol to which a higher fatty acid is added, and an ethylene oxide / propylene oxide copolymer.

Examples of the anionic surfactant include carboxylic acids (salts), sulfuric acid ester salts of higher alcohols and higher alcohol ethers, sulfonates, phosphoric acid ester salts of higher alcohols and higher alcohol ethers, and the like.

Examples of the cationic surfactant include quaternary ammonium salt type cationic surfactants such as lauryltrimethylammonium chloride and oleylmethylethylammonium ethosulfate, amine salt type cationic surfactants such as polyoxyethylene laurylamine Etc.) and the like.

Examples of the amphoteric surfactant include amino acid type amphoteric surfactants such as sodium laurylaminopropionate and betaine type amphoteric surfactants such as stearyldimethylbetaine and lauryldihydroxyethylbetaine .

The sizing agent of the present invention can exert excellent film flexibility and uniform adhesion after limiting the use of the surfactant. When a large amount of the surfactant is contained, heat resistance of the sizing agent is lowered, which is not preferable. From this viewpoint, the proportion of the surfactant in the nonvolatile matter of the sizing agent is preferably 20% by weight or less, more preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% .

The concentration of the non-volatile component in the sizing agent of the present invention is not particularly limited, and is appropriately selected in consideration of stability as an aqueous dispersion, viscosity to be easily handled as a product, and the like. Considering the transportation cost of the product, the weight ratio of non-volatile matter in the sizing agent is preferably 10 to 100% by weight, more preferably 15 to 100% by weight, and particularly preferably 20 to 100% by weight.

The total weight ratio of water to non-volatile matter in the sizing agent is preferably 90% by weight or more, more preferably 95% by weight or more, more preferably 99% by weight or more, and particularly preferably 100% by weight . When the content of the organic solvent or other low boiling point compound is less than 90% by weight, that is, when the organic solvent or other low boiling point compound does not remain as nonvolatile matter at the time of heat treatment, Which may be undesirable.

In addition to the abovementioned human safety and prevention of environmental pollution, the above-mentioned aqueous dispersion or aqueous solution is preferably free of a solvent other than water such as an organic solvent from the viewpoint of prevention of thickening and solidification of the aqueous dispersion or aqueous solution over time, Is preferably 10% by weight or less, more preferably 5% by weight or less, and even more preferably 1% by weight or less based on the entire sizing agent.

The method of producing the sizing agent of the present invention as an aqueous dispersion is not particularly limited, and a known method can be adopted. As described above, there are a method of making an aqueous dispersion in the production of an aromatic polyester-based urethane resin, a method of emulsifying and dispersing the components constituting the sizing agent in hot water under stirring, , Mixing the components constituting the sizing agent, warming the resulting mixture to a temperature above the softening point, and gradually adding the mechanical shearing force by using a homogenizer, a homomixer, a ball mill or the like, And a method of introducing and phase-inversion emulsification.

[Reinforced fiber strand and its manufacturing method]

The reinforcing fiber strand of the present invention is a reinforcing fiber to which reinforcing fiber sizing agent is adhered to a raw material reinforcing fiber strand to reinforce the matrix resin. The reinforcing fiber strand of the present invention is excellent in adhesion to a matrix resin. Further, since the reinforcing fiber useful sizing agent having excellent heat resistance is treated, thermal decomposition of the sizing agent can be suppressed at the time of high-temperature treatment with the matrix resin, and inhibition of adhesion with the matrix resin due to thermal decomposition can be suppressed. The matrix resin is preferably a thermoplastic resin in that the sizing agent of the present invention has a higher effect of improving the adhesiveness.

The amount of sizing nonvolatile matter adhered to the raw material reinforcing fiber strand can be appropriately selected, and the amount of the reinforcing fiber strand required to have the required function is preferably 0.1 to 20% by weight based on the raw material reinforcing fiber strand Do. In the reinforcing fiber strands of the long fiber form, the amount of the reinforcing fiber strands is preferably 0.1 to 10 wt%, more preferably 0.5 to 5 wt%, based on the raw material reinforcing fiber strand. In the case of a strand of a short fiber form (cut into a predetermined length), it is more preferably 0.5 to 20% by weight, and further preferably 1 to 10% by weight.

If the amount of the sizing agent to be adhered is small, the effects of the present invention regarding heat resistance, resin impregnability, and adhesiveness are difficult to obtain, and the strength of the reinforcing fiber strands is insufficient and the handling property is deteriorated. In addition, if the sizing agent is adhered too much, the reinforcing fiber strands become too rigid, which may result in poor handling properties or poor resin impregnability during molding of the composite material.

A method for producing a reinforcing fiber strand includes a step of preparing a treatment liquid containing the above sizing agent and having a weight ratio of nonvolatile matter of 0.5 to 10% by weight and a total weight ratio of water and nonvolatile matter of 90% And an adhering step of adhering the treatment liquid to the raw material reinforcing fiber strands so that the adhered amount of the nonvolatile matter to the raw material reinforcing fiber strand becomes 0.1 to 20 wt%.

In the preparation process, the weight ratio of the non-volatile matter occupying the treatment liquid is more preferably 0.5 to 10% by weight, and further preferably 1 to 5% by weight. The total weight ratio of water and non-volatile components is more preferably 95% by weight or more, further preferably 99% by weight or more, and particularly preferably 100% by weight.

In the adhering step, the preferable amount of the nonvolatile matter to be adhered is the same as in the preceding paragraph. The method of attaching the sizing agent to the raw material reinforcing fiber strand is not particularly limited, but it is sufficient that the sizing agent is attached to the raw material reinforcing fiber strands by a kiss roller method, a roller dipping method, a spray method, or other known methods. Among these methods, the roller dipping method is preferable because the sizing agent can be uniformly adhered to the raw material reinforcing fiber strands.

The drying method of the obtained adherend is not particularly limited, and it can be heated and dried by, for example, a heating roller, hot air or a hot plate.

When adhering to the raw material reinforcing fiber strands of the sizing agent of the present invention, all of the constituent components of the sizing agent may be mixed and then adhered, or the constituent components may be separately adhered in two or more stages. In addition, within the range not impairing the effect of the present invention, it is possible to use a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, and a phenol resin and / or a polyolefin resin, a polyester resin, a nylon resin , Acrylic resin, or the like may be attached to the raw material reinforcing fiber strand.

The reinforcing fiber strand of the present invention is used as a reinforcing fiber of a composite material comprising various resins as a matrix resin, and may be in the form of a long fiber or a short fiber.

The (reinforcing) fiber strands to which the sizing agent of the present invention can be applied include various inorganic fibers such as carbon fibers, glass fibers and ceramic fibers, aramid fibers, polyethylene fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, Strands of various organic fibers such as polyethylene naphthalate fibers, polyarylate fibers, polyacetal fibers, PBO fibers, polyphenylene sulfide fibers and polyketone fibers. As raw material reinforcing fiber strands, carbon fibers, aramid fibers, polyethylene fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, polyarylate fibers, At least one kind of strand selected from polyacetal fiber, PBO fiber, polyphenylene sulfide fiber and polyketone fiber is preferable, and carbon fiber strand is more preferable.

[Fiber reinforced composite material]

The fiber-reinforced composite material of the present invention includes a matrix resin and the reinforcing fiber strand described above. The reinforcing fiber strands are treated by the sizing agent of the present invention, and the sizing agent is uniformly adhered, and the affinity with the reinforcing fiber strand and the matrix resin becomes good, and the fiber reinforced composite material becomes excellent in adhesiveness. In addition, thermal decomposition of the sizing agent during the high-temperature treatment can be suppressed and inhibition of adhesion with the matrix resin due to thermal decomposition can be suppressed. Here, the matrix resin refers to a matrix resin made of a thermosetting resin or a thermoplastic resin, and may include one or more kinds thereof. The thermosetting resin is not particularly limited, and examples thereof include an epoxy resin, a phenol resin, an unsaturated polyester resin, a vinyl ester resin, a cyanate ester resin and a polyimide resin. The thermoplastic resin is not particularly limited and examples thereof include polyolefin resin, polyamide resin, polycarbonate resin, polyester resin, polyacetal resin, ABS resin, phenoxy resin, polymethyl methacrylate resin, polyphenylene sulfide resin, Polyether imide resins, polyether ketone resins, and the like. Of these, a polyamide-based resin having a higher adhesiveness improving effect by the sizing agent of the present invention is preferable. Here, the polyamide-based resin is a polymer compound having a plurality of amide groups in the main chain synthesized from dibasic fatty acids and diamines,? -Amino acids, lactams or derivatives thereof, and also includes homopolymers and copolymers do. It is also possible to use a modified product obtained by introducing a substituent at the main chain or terminal.

These matrix resins may be partially or wholly modified for the purpose of further improving the adhesiveness with the reinforcing fiber strand. Of these, the matrix resin is preferably a thermoplastic resin, and more preferably a polyamide-based resin, from the viewpoint that the effect of improving the adhesiveness by the sizing agent of the present invention is higher.

The method for producing the fiber-reinforced composite material is not particularly limited, and known methods such as compound injection molding using short fibers, long fiber pellets, press molding with UD sheet, fabric sheet, and other filament winding molding can be adopted have.

When the thermoplastic matrix resin and the reinforcing fiber are kneaded, the thermoplastic matrix resin is kneaded with the reinforcing fiber at a temperature of 200 ° C to 400 ° C above the melting point in the case of a high melting point such as general engineer plastic or super engineered plastic, do.

The content of the reinforcing fiber strand in the fiber reinforced composite material is not particularly limited, and may be appropriately selected depending on the type and shape of the fiber, the type of the matrix resin, and the like. The fiber reinforced composite material is preferably 5 to 70% , More preferably from 20 to 60% by weight.

<Examples>

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. The percent (%) and parts shown in the following examples represent "% by weight" and "parts by weight" unless otherwise specified. The measurement of each characteristic value was carried out based on the following method.

&Lt; Glass transition point &gt;

The measurement was carried out in accordance with JIS-K7121 under the conditions of a sample weight of about 10 mg and a temperature rise rate of 10 DEG C / min according to a differential scanning calorimeter (DSC) (JADE DSC LAB SYSTEM, manufactured by PerkinElmer Instruments Co., Ltd.). Specifically, a sample precisely measured at 10 ± 1 mg is set in a differential scanning calorimeter and the temperature is raised to the sample melting temperature Tm + 30 ° C. confirmed in the preliminary measurement. Next, the temperature is lowered to the glass transition point Tg-40 ° C determined in the preliminary measurement, and then the temperature is raised to 200 ° C at a temperature rising rate of 10 ° C / minute. A point at which a straight line extending equidistant from the straight line extending from each of the reference lines and a curve of the step-shaped change portion crosses the glass transition point Tg (unit: ° C) in the portion showing the step shape change of the obtained DSC curve .

<Dynamic surface tension>

The sizing agent was diluted with water so as to be a 2 wt% non-volatile content aqueous solution, and was measured at 25 DEG C in a bubble generation interval (bubble plate) of 20 to 1000 msec using a spindle dynamic surface tension meter (BP- Dynamic surface tension was measured, and dynamic surface tension measurements at bubble interval (bubble plate) 100 msec were read.

<Weight reduction rate>

The sizing agent is heat-treated at 105 캜 to remove the solvent and the like, and reaches a constant weight to obtain a nonvolatile matter of the sizing agent. About 4 mg of the obtained nonvolatile matter was taken into an aluminum pan whose weight was already known, and the weight (W ₁ ) was measured. The nonvolatile matter contained in the aluminum pan was set on a differential thermal balance TG-8120 (manufactured by Rigaku Corporation), and the temperature was raised from 25 DEG C to 500 DEG C in the air at a temperature rising rate of 20 DEG C / W ₂ ) were measured. The weight reduction ratio was then calculated by the following equation.

Weight reduction rate (%) = ((W ₁ -W ₂ ) / W ₁ ) × 100

<Adhesiveness>

Adhesiveness was evaluated by an aesthetic method using a composite material interface property evaluation device HM410 (manufactured by Toei Industry Co., Ltd.).

The carbon fiber filaments were taken out from the carbon fiber strands produced in Examples and Comparative Examples and set in the composite interface property evaluation apparatus. A drop of the polyamide resin T-663 (manufactured by Toyo Yakyu Co., Ltd.) melted on the apparatus was formed on the carbon fiber filament, and sufficiently cooled at room temperature to obtain a sample for measurement. Again, the test sample was set on the device, the drop was sandwiched between the device blades, and the maximum pull out load (F) was measured when the carbon fiber filament was run on the device at a speed of 0.06 mm / min to remove the drop from the carbon fiber filament.

The interfacial shear strength? Was calculated by the following formula, and the adhesion between the carbon fiber filament and the polyamide-based resin was evaluated.

Interface shear strength? (Unit: MPa) = F /? Dl

(F: maximum drawing load d: diameter of carbon fiber filament 1: diameter of particle in the direction of drop drawing)

&Lt; Flexibility of film (openability) &gt;

The sizing agent was adhered to the sizing agent-treated carbon fiber strand (fineness: 800 tex, number of filaments: 12,000) such that the adhered amount of the sizing agent nonvolatile matter was 1.0% by weight. The flexibility (openness) of the obtained adhered carbon fiber strand (length: about 50 cm) was measured by a soft touch tester (HANDLE-O-METERHOM-2 manufactured by TAIYO Scientific Co., Ltd., slit width 5 mm).

The measurement was carried out ten times, and it was judged that the smaller the average value was, the better the film flexibility of the sizing agent imparted to the carbon fiber strand was. Further, it was determined that the smaller the average value, the better the openability of the carbon fiber strand.

(Criteria)

?: 50 g or less Carbon fiber strands are smooth, and the sizing agent has a very good film flexibility. In addition, the carbon fiber strand has very good openability.

?: 50 g to 60 g The carbon fiber strands are smooth, and the sizing agent has good flexibility. Also, the carbon fiber strand has good openability.

X: 60 g or more Carbon fiber strands are hard, and the flexibility of the sizing agent is poor. Also, the carbon fiber strand has poor openability.

<Average particle diameter>

The sizing agent was diluted with water to have a transmittance of 70% or more, and the average value was calculated from the particle size distribution measured with a laser diffraction / scattering type particle size distribution analyzer (Horiba LA-910).

[Synthesis of polyester polyol]

(Synthesis Example 1)

In the reactor, 498.4 parts of terephthalic acid, 448.6 parts of isophthalic acid, 186.2 parts of ethylene glycol, 343.2 parts of neopentyl glycol and 0.2 parts of dibutyltin oxide were placed in a reactor and esterification reaction was carried out at 190 to 240 ° C for 10 hours. An aromatic polyester polyol 1 having an average molecular weight of 1800 and a hydroxyl value of 60 mgKOH / g was obtained.

(Synthesis Example 2)

An aromatic polyester polyol 2 having a number average molecular weight of 3,000 and a hydroxyl value of 50 mg KOH / g was obtained in the same manner as in Synthesis Example 1, except that the raw materials and amounts thereof were changed to those shown in the table.

(Synthesis Example 3)

An aliphatic polyester polyol 3 having a number average molecular weight of 2000 and a hydroxyl value of 56 mg KOH / g was obtained in the same manner as in Synthesis Example 1, except that the starting materials and amounts thereof were changed to those shown in the table.

The raw materials and amounts used for the synthesis of the aromatic polyester polyols 1 and 2 and the aliphatic polyester polyol 3 are shown in Table 1.

[Synthesis of aromatic polyester-based urethane resin]

(Production Example 1-1)

163.9 parts of the above-prepared aromatic polyester polyol 1 as an aromatic polyester polyol (B1) was added to a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and dehydrated at 120-130 ° C under reduced pressure. Thereafter, the mixture was cooled to 50 占 폚, and 43.2 parts of polyethylene glycol (weight average molecular weight 400) as polyalkylene glycol (B4), 12.7 parts of trimethylolpropane as trifunctional or more active hydrogen group-containing compound (B3) and 150 parts of methyl ethyl Ketone. After sufficiently stirring and mixing, 65.8 parts of hexamethylene diisocyanate as the organic polyisocyanate compound (A) was added and the mixture was heated to 75 ° C and reacted for 2 hours to obtain a prepolymer solution having a terminal isocyanate group. After completion of the reaction, the mixture was cooled to 40 占 폚 and 14.5 parts of 2,2-dimethylolpropionic acid as the active hydrogen group-containing compound (B2) having a carboxyl group was added thereto and reacted at 75 占 폚 for 2 hours. After completion of the reaction, the mixture was cooled to 40 ° C and 11.5 parts of dimethylethanolamine as a basic component was added. After the neutralization reaction, 1200 parts of water was added to form a water emulsion. The resulting water emulsion was subjected to a reduced pressure treatment at 65 占 폚 to remove methyl ethyl ketone and the water content was adjusted to obtain an aromatic polyester-based urethane resin 1-1 as a water emulsion having a nonvolatile content of 20% by weight.

(Production Examples 1-2 to 1-10)

(B1), an active hydrogen group-containing compound (B2) having a carboxyl group, an active hydrogen group-containing compound (B3) having three or more functional groups, a polyalkylene glycol (B4), a basic component Aromatic polyurethane-based urethane resin 1-2 to 1-10, which is a water emulsion having a nonvolatile content of 20% by weight, was obtained in the same manner as in Production Example 1-1, except that .

[Synthesis of urethane resin for comparative example]

(Production Examples 2-1 to 2-4)

(B1), an active hydrogen group-containing compound (B2) having a carboxyl group, an active hydrogen group-containing compound (B3) having three or more functional groups, a polyalkylene glycol (B4), a basic component Was changed to the parts shown in Table 3 and parts by weight, the same procedure as in Production Example 1-1 was carried out except that the aromatic polyester-based urethane resins 2-1 and 2-2, which were water emulsions having a nonvolatile content of 20% by weight and the aliphatic polyester Based urethane resins 2-3 and 2-4 were obtained. The aliphatic polyester-based urethane resins 2-3 and 2-4 use an aliphatic polyester polyol 3 instead of the aromatic polyester polyol (B1).

(Preparation Example 2-5)

172.2 parts of the prepared aromatic polyester polyol 1 was added to a four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and dehydrated at 120-130 ° C under reduced pressure. Then, the mixture was cooled to 50 DEG C, and 45.3 parts of polyethylene glycol (weight average molecular weight 400), 13.3 parts of trimethylol propane and 150 parts of methyl ethyl ketone were added. After thoroughly stirring and mixing, 69.1 parts of hexamethylene diisocyanate was added and the mixture was heated to 75 DEG C and reacted for 2 hours. After the completion of the reaction, 1200 parts of water was added, but a stable water emulsion was not obtained and a water emulsion of the aromatic polyester-based urethane resin 2-5 could not be obtained.

(Preparation Example 2-6)

137.1 parts of polyethylene glycol (weight average molecular weight 400), 22.2 parts of trimethylol propane and 150 parts of methyl ethyl ketone were added to a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, thoroughly stirred and mixed, and then 115.7 parts of hexamethylene Diisocyanate was added and the mixture was heated to 75 캜 and reacted for 2 hours to obtain a prepolymer solution having a terminal isocyanate group. After completion of the reaction, the reaction mixture was cooled to 40 ° C and 25.4 parts of dimethylol propionic acid was added thereto, followed by reaction at 75 ° C for 2 hours. After completion of the reaction, the reaction mixture was cooled to 40 ° C and 20.2 parts of dimethylethanolamine was added to neutralize the reaction mixture, and then 1200 parts of water was added thereto to prepare a water emulsion. The resulting water emulsion was subjected to a reduced pressure treatment at 65 캜 to distill off methyl ethyl ketone and adjust the water content to obtain a urethane resin 2-6 which is a water emulsion having a nonvolatile content of 20% by weight.

Tables 2 and 3 show the parts by weight of the organic polyisocyanate compound (A) and the active hydrogen group-containing compound (B) constituting these urethane resins.

Tables 4 and 5 show the ratios of the organic polyisocyanate compound (A) and the active hydrogen group-containing compound (B) constituting these urethane resins. The numerical values outside the parentheses indicate the ratio (mol%) of the isocyanate group of the organic polyisocyanate compound (B) and the active hydrogen group ratio (mol%) of the active hydrogen group-containing compound (B). The numerical values in parentheses indicate the ratio (mol%) of the organic polyisocyanate compound (A) and the ratio (mol%) of the active hydrogen group-containing compound (B).

(Examples 1 to 10 and Comparative Examples 1 to 6)

The aqueous dispersions of the urethane resins 1-1 to 1-10 and 2-1 to 2-6 prepared above were diluted with water to prepare a sizing agent having a nonvolatile fraction concentration of 10% by weight. Using the obtained sizing agent, the glass transition point, dynamic surface tension, weight reduction rate, and film flexibility were evaluated according to the above-described method.

Subsequently, the fiber was impregnated and impregnated with a sizing agent prepared from sizing-untreated carbon fiber strands (fineness: 800 tex, filament count: 12,000), and then subjected to hot-air drying at 105 ° C for 15 minutes so that the amount of nonvolatile matter adhered to the carbon fiber strands To obtain a 5% by weight sizing agent treated carbon fiber strand. The adhesion of the matrix resin to the strands was evaluated according to the above-mentioned method. These results are shown in Tables 2 and 3.

As can be seen from Tables 2 and 3, in Examples 1 to 10, the interfacial shear strengths of the reinforcing fibers and the matrix resin were two to three times larger than those of Comparative Examples 1 to 6, and the adhesiveness was remarkably improved.

In Examples 1 to 3, 5 and 7 to 10 using polyalkylene glycol (B4), the film flexibility was improved.

[Production example of the water dispersions C1 to C4 of the ester compound (C)] [

(Production Example C1)

A composition comprising bisphenol A diglycidyl ether acrylic acid adduct / ethylene oxide 150 mol addition-cured castor oil ether = 80/20 (weight ratio) was added to the emulsification apparatus and water was gradually added under stirring to form phase emulsion, thereby obtaining a homogeneous bisphenol A di To obtain a water dispersion C1 of a glycidyl ether acrylic acid adduct. The nonvolatile fraction of the water dispersion C1 was 40% by weight.

The average particle diameter of the ester compound of the water dispersion C1 was measured and found to be 0.19 mu m. In addition, the water dispersion C1 did not exhibit aggregation separation or float separation at 50 DEG C for one month, and was excellent in static stability.

(Production Example C2)

In the same manner as in Production Example C1 except that 4 mol of ethylene oxide adduct and 4 mol of bisphenol A acrylic acid adduct were used in place of bisphenol A diglycidyl ether acrylic acid adduct in Production Example C1, 4 mol of ethylene oxide was added to the aqueous dispersion of bisphenol A acrylic acid adduct C2. The nonvolatile fraction of the water dispersion C2 was 40% by weight.

The average particle diameter of the ester compound of the water dispersion C2 was measured to be 0.25 占 퐉. In addition, the water dispersion C2 did not exhibit aggregation separation or float separation even when left at 50 DEG C for one month, and was excellent in the stability of the gas.

(Production Example C3)

(Weight average molecular weight: 15,000, oxypropylene / oxyethylene = 20/80 (weight ratio)) of 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid / ) = 70/20/10 (weight ratio) was put into an emulsification apparatus, and water was slowly added thereto under stirring to effect phase inversion emulsification to obtain a homogeneous aqueous dispersion C3 of 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid &Lt; / RTI &gt; The nonvolatile fraction of the water dispersion C3 was 40% by weight.

The average particle diameter of the ester compound of the water dispersion C3 was measured and found to be 0.29 탆. In addition, the water dispersion C3 did not exhibit aggregation separation or float separation even when left at 50 占 폚 for one month, and was excellent in stability of the gas.

(Production Example C4)

(Weight average molecular weight: 15,000, oxypropylene / oxyethylene = 20/80 by weight) / oxyethylene-oxypropylene block polymer (weight average molecular weight: 2,000, oxypropylene (Weight ratio) = 70/15/15 (weight ratio) was put into an emulsification apparatus, and water was gradually added thereto under stirring to effect phase inversion emulsification to obtain a homogeneous water of trimethylolpropane trimethacrylate To obtain a C4 derivative. The nonvolatile content C4 of the water dispersion was 40% by weight.

The average particle diameter of the ester compound of the water dispersion C4 was measured and found to be 0.21 탆. Also, the aqueous dispersion C4 did not exhibit any aggregation separation or float separation even after being left at 50 占 폚 for one month, and the dispersion stability was excellent.

(Examples 11 to 43)

The aromatic polyester-based urethane resins 1-1 and 1-4, the aqueous dispersion of the ester compound (C) and the components shown below were mixed and stirred so as to have the non-volatile content shown in Tables 6 to 8, And diluted with water to prepare a sizing agent having a nonvolatile matter concentration of 10% by weight. In addition, the numerical values in Tables 6 to 8 indicate the weight ratio of each component occupying the nonvolatile component of the sizing agent (in the case of the water dispersion, the nonvolatile component thereof). For example, the values of C1 to C4 in Tables 6 to 8 indicate the weight ratios of the nonvolatile fractions of the water dispersions C1 to C4 occupying the nonvolatile matter of the sizing agent. Using the obtained sizing agent, dynamic surface tension, film flexibility (openness) and weight reduction rate were evaluated according to the above-mentioned method.

[Ester compound (C)]

C5: polyalkylene glycol diacrylate, weight average molecular weight 400

[Polyoxyalkylene alkyl ether (D)]

D1: isobutyl alcohol PO 7 mole EO 7 mole adduct of block

D2: 2-ethylhexyl alcohol PO 2 mole EO 1 mole block adduct

D3: 2-ethylhexyl alcohol EO 8 mole adduct

D4: lauryl alcohol EO 7 mole adduct

Subsequently, the fiber was impregnated and impregnated with a sizing agent prepared from sizing-untreated carbon fiber strands (fineness: 800 tex, filament count: 12,000), and then subjected to hot-air drying at 105 ° C for 15 minutes so that the amount of nonvolatile matter adhered to the carbon fiber strands To obtain a 5% by weight sizing agent treated carbon fiber strand. For the present strand, the adhesive property of the matrix resin was evaluated by the above-mentioned method. These results are shown in Tables 6-8.

As can be seen from Tables 6 to 8, in Examples 11 to 43, the interfacial shear strengths of the reinforcing fibers and the matrix resin were two to three times higher than those of Comparative Examples 1 to 6, and the adhesiveness was remarkably improved. Examples 11 to 42 are more excellent in openability than Examples 1 to 10.

Fiber reinforced composites reinforced with matrix fibers are used for automotive applications, aerospace applications, sports and leisure applications, and general industrial applications. Examples of the reinforcing fiber include various inorganic fibers such as carbon fiber, glass fiber and ceramic fiber, and various organic fibers such as aramid fiber, polyamide fiber and polyethylene fiber. The sizing agent of the present invention can be suitably used for reinforcing fibers for reinforcing a matrix resin.

Claims (19)

An aromatic polyester-based urethane resin as essential components,
The aromatic polyester-based urethane resin can be obtained by reacting the organic polyisocyanate compound (A) with the active hydrogen group-containing compound (B)
Wherein the active hydrogen group-containing compound (B) comprises an aromatic polyester polyol (B1), an active hydrogen group-containing compound (B2) having a carboxyl group and an active hydrogen group-containing compound (B3) having three or more functional groups. The method according to claim 1,
Wherein the ratio of the active hydrogen groups in the aromatic polyester polyol (B1) is 5 to 80 mol%, the active hydrogen group having the carboxyl group (B) is 100 mol%, and the ratio of the active hydrogen groups in the total of the active hydrogen group- Containing compound (B2) is 5 to 60 mol%, and the active hydrogen group-containing compound (B3) having 3 or more functional groups is 5 to 70 mol%. 3. The method according to claim 1 or 2,
Wherein the active hydrogen group-containing compound (B) further comprises a polyalkylene glycol (B4) having a weight average molecular weight of 100 to 2000. The method of claim 3,
Wherein the active hydrogen group ratio of the polyalkylene glycol (B4) is 10 to 40 mol%, based on 100 mol% of active hydrogen groups in the active hydrogen group-containing compound (B) as a whole. An aromatic polyester-based urethane resin as essential components,
Wherein the aromatic polyester-based urethane resin is composed of a constituent unit (a) derived from the organic polyisocyanate compound (A) and a constituent unit (b) derived from the active hydrogen group-containing compound (B)
(B2) derived from an active hydrogen group-containing compound (B2) having a carboxyl group and a constituent unit (b2) derived from an aromatic polyester polyol (B1) And a constituent unit (b3) derived from the compound (B3). 6. The method of claim 5,
, The proportion of the constituent unit (b1) in the total of the constituent units (b) is 5 to 80 mol%, the proportion of the constituent unit (b2) is 5 to 60 mol% From 2 to 70 mol%. The method according to claim 5 or 6,
Wherein the structural unit (b) further comprises a structural unit (b4) derived from a polyalkylene glycol (B4) having a weight average molecular weight of 100 to 2000. 8. The method of claim 7,
And the proportion of the structural unit (b4) in the whole of the structural unit (b) is 10 to 40 mol%. 9. The method according to any one of claims 1 to 8,
Wherein the aromatic polyester-based urethane resin has a glass transition point of not higher than 40 占 폚. 10. The method according to any one of claims 1 to 9,
When the dynamic surface tension when water is added and the non-volatile content of the sizing agent is adjusted to 2 wt% is measured under the condition that one foam is generated at 100 milliseconds by the maximum vapor pressure method, it is 40 to 70 mN / m Reinforcing fiber useful sizing agent. 11. The method according to any one of claims 1 to 10,
Wherein the active hydrogen group-containing compound (B2) having a carboxyl group is at least one selected from the group consisting of 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid. 12. The method according to any one of claims 1 to 11,
Wherein the active-hydrogen-group-containing compound (B3) having three or more functional groups is at least one member selected from the group consisting of trimethylolethane, trimethylolpropane and pentaerythritol. 13. The method according to any one of claims 1 to 12,
In addition, a reinforcing sizing agent sizing agent containing an ester compound (C) having at least one terminal of a compound main chain with a vinyl ester group, an acrylate group or a methacrylate group. 14. The method according to any one of claims 1 to 13,
In addition, a reinforcing sizing agent sizing agent containing a polyoxyalkylene alkyl ether (D) which is an alkylene oxide adduct of a monovalent alcohol having 4 to 14 carbon atoms. 15. The method according to any one of claims 1 to 14,
Wherein the weight loss ratio of the non-volatile matter when the non-volatile content of the reinforcing fiber useful sizing agent is raised to 300 캜 is 15% by weight or less. A reinforcing fiber strand having the reinforcing fiber beneficial sizing agent according to any one of claims 1 to 15 adhered to the reinforcing fiber strand. 17. The method of claim 16,
Wherein the raw material reinforcing fiber strand is a raw carbon fiber strand. A fiber-reinforced composite material comprising a matrix resin and the reinforcing fiber strand according to claim 16 or 17. 19. The method of claim 18,
Wherein the matrix resin is a thermoplastic resin.