JP7517890B2 - Aqueous Composition - Google Patents

Description

The present invention relates to an aqueous composition.

Aqueous emulsions of acid-modified polyolefins have been developed, for example, as bundling agents for carbon fibers (see, for example, Patent Document 1).

JP 2015-131889 A

However, even the technology of Patent Document 1 above does not provide sufficient focusing properties, and improvements are required. The present invention aims to provide an aqueous composition with excellent focusing properties.

The present inventors conducted research to achieve the above object, and arrived at the present invention. That is, the present invention is an aqueous composition comprising an aqueous medium, a (partial) neutralization product (XC) of an acid-modified polyolefin (X) and a base (C), and a polyfunctional amine (am), in which (X) comprises, as constituent raw materials, a polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly)carboxylic acid (anhydride) (B), and (A) comprises, as constituent monomers, ethylene and an α-olefin (having 3 to 8 carbon atoms), and the weight ratio of the ethylene to the α-olefin [ethylene/α-olefin] is 3/97 to 50/50.

The aqueous composition (Y) of the present invention has the following effects.
(1) The aqueous composition of the present invention has excellent storage stability.
(2) The inorganic fibers treated with the aqueous composition of the present invention have excellent bundling properties.
(3) The inorganic fibers obtained by using the aqueous composition of the present invention generate little fluff.
(4) It gives excellent mechanical strength to fiber-reinforced composite materials.

The aqueous composition (Y) of the present invention is an aqueous composition comprising an aqueous medium, a (partial) neutralization product (XC) of an acid-modified polyolefin (X) and a base (C), and a polyfunctional amine (am), in which the (X) comprises, as constituent raw materials, a polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly)carboxylic acid (anhydride) (B), the (A) comprises, as constituent monomers, ethylene and an α-olefin (having a carbon number of 3 to 8), and the weight ratio of the ethylene to the α-olefin [ethylene/α-olefin] is 3/97 to 50/50.
In the present invention, "(partially) neutralized product" means "neutralized product or partially neutralized product", and may be partially neutralized or may be 100% neutralized. In addition, "unsaturated (poly)carboxylic acid (anhydride)" means "at least one selected from the group consisting of unsaturated monocarboxylic acids, unsaturated polycarboxylic acids, and unsaturated polycarboxylic acid anhydrides".

<Polyolefin (A) having carbon-carbon double bonds>
The polyolefin (A) having a carbon-carbon double bond in the present invention contains ethylene and an α-olefin (having 3 to 8 carbon atoms) as constituent monomers.
Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.
Although two or more kinds of α-olefins may be used in combination, it is preferable to use one kind.
Of the above α-olefins, propylene is preferred from the viewpoints of mechanical strength and ease of production of (A).

The weight ratio of ethylene and an α-olefin (having 3 to 8 carbon atoms), which are constituent monomers of the polyolefin (A) having a carbon-carbon double bond, [ethylene/α-olefin] is 3/97 to 50/50, preferably 5/95 to 40/60, and more preferably 10/90 to 30/70.
If the weight ratio [ethylene/α-olefin] is less than 3/97, the sizing ability is poor, and if it exceeds 50/50, the mechanical strength is poor.
The weight ratio [ethylene/α-olefin] can be calculated, for example, by ¹ H-NMR. The weight ratio of ethylene to α-olefin having 3 to 8 carbon atoms in (A) can be adjusted by the weight ratio of ethylene to α-olefin having 3 to 8 carbon atoms in the high molecular weight polyolefin (A0) to be described later as a raw material.

The (A) may contain other monomers as constituent monomers in addition to ethylene and α-olefins. In that case, the weight of the other monomers is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight or less, based on the weight of all the monomers constituting the (A).
Examples of the other monomers include α-olefins having a carbon number [sometimes abbreviated as C] of 9 to 30 (e.g., 1-decene, 1-dodecene, etc.), and C4 to C30 unsaturated monomers other than α-olefins (e.g., olefins such as 2-butene and isobutene, and vinyl monomers such as styrene, acrylonitrile, acrylamide, and vinyl acetate).

From the viewpoints of mechanical strength and storage stability, the number average molecular weight (Mn) of the polyolefin (A) having carbon-carbon double bonds is preferably 800 to 50,000, more preferably 1,500 to 40,000, and particularly preferably 2,000 to 30,000.

In the present invention, the conditions for measuring Mn and weight average molecular weight (Mw) by GPC (gel permeation chromatography) are as follows.
Apparatus: High temperature gel permeation chromatograph
["Alliance GPC V2000", manufactured by Waters Corporation]
Detector: Refractive index detector Solvent: Orthodichlorobenzene Reference material: Polystyrene Sample concentration: 3 mg/ml
Column stationary phase: PLgel 10 μm, MIXED-B 2 columns in series
[Manufactured by Polymer Laboratories, Inc.]
Column temperature: 135°C

The number of double bonds per 1,000 carbon atoms in the polyolefin (A) [the number of carbon-carbon double bonds at the molecular terminals and/or in the molecular chain of (A)] is preferably 1 to 20, more preferably 1.5 to 18, and particularly preferably 2 to 15, from the viewpoints of reactivity with the (poly)carboxylic acid (anhydride) (B) described below and productivity.
Here, the number of double bonds can be determined from the ^1H -NMR (nuclear magnetic resonance) spectroscopy spectrum of (A). That is, peaks in the spectrum are assigned, and the relative value between the number of double bonds in (A) and the number of carbon atoms in (A) is determined from the integral value derived from the double bonds in (A) at 4.5 to 6 ppm and the integral value derived from (A), and the number of double bonds in the molecular terminal and/or molecular chain per 1,000 carbons in (A) is calculated. The number of double bonds in the examples described below follows this method.

The isotacticity of the chain portion of units derived from α-olefin in the polyolefin (A) having a carbon-carbon double bond (hereinafter abbreviated as α-olefin unit chain portion) is preferably 1 to 50%, more preferably 5 to 45%, and particularly preferably 10 to 40%, from the viewpoints of fuzz and bundling ability.
The isotacticity of the chain of α-olefin units in the polyolefin (A) tends to be directly reflected in the isotacticity of the chain of α-olefin units in the acid-modified polyolefin (X) described below.

The isotacticity can be calculated, for example, by using ¹³ C-NMR (nuclear magnetic resonance spectroscopy). It is generally known that a side chain methyl group is affected by the configuration (meso or racemo) of the methyl groups on both sides (triad), on both sides of the triad (pentad), and on both sides of the pentad (heptad), and peaks are observed at different chemical shifts. The stereoregularity is generally evaluated for the pentad, and the isotacticity in the present invention can also be calculated based on the evaluation of the pentad.
That is, when the α-olefin is propylene, the carbon peaks derived from the side chain methyl groups in propylene obtained by ^13C -NMR are taken as the peaks of each pentad (H), and the peaks derived from the methyl groups in isotactic propylene in which the pentad is formed only of a meso structure (Ha), the isotacticity is calculated by the following formula:
Isotacticity (%) = [(Ha) / Σ(H)] × 100 (1)
In the formula, H a is the peak height of the isotactic signal (the pentad is formed only in the mesostructure), and H is the height of each peak of the pentad.
The isotacticity of the α-olefin unit sequence portion of (X) described below can also be measured in the same manner as above.

The method for producing the polyolefin (A) having a carbon-carbon double bond in the present invention can be, for example, a method of thermally degrading a high molecular weight polyolefin (A0) (preferably Mn of 60,000 to 400,000, more preferably Mn of 80,000 to 250,000).

The thermal degradation method includes a method of thermally degrading the high molecular weight polyolefin (A0) in the absence of an organic peroxide, for example, at 300 to 450° C. for 0.5 to 10 hours, and a method of thermally degrading the high molecular weight polyolefin in the presence of an organic peroxide [for example, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane], for example, at 180 to 300° C. for 0.5 to 10 hours.
Of these, from the viewpoint of modification characteristics, the method (1) is preferred, which can easily give a polymer having a larger number of double bonds at the molecular terminals and/or in the molecular chain.

The weight ratio [ethylene/α-olefin] of ethylene and α-olefin, which are monomers constituting the above (A), tends to be maintained the same as the weight ratio [ethylene/α-olefin] of the high molecular weight polyolefin (A0).
Furthermore, the higher the thermal degradation temperature and the longer the thermal degradation time, the larger the number of double bonds per 1,000 carbon atoms tends to be.
Furthermore, the smaller the Mn of (A0), the higher the thermal degradation temperature, and the longer the thermal degradation time, the smaller the Mn of (A) tends to be.
In addition, the higher the isotacticity of (A0), the higher the isotacticity of (A) tends to be.

<Unsaturated (poly)carboxylic acid (anhydride) (B)>
The unsaturated (poly)carboxylic acid (anhydride) (B) in the present invention includes (poly)carboxylic acid (anhydrides) having one polymerizable unsaturated group and having 3 to 30 carbon atoms [hereinafter sometimes abbreviated as C].
Among the unsaturated (poly)carboxylic acids (anhydrides) (B), examples of the unsaturated monocarboxylic acids include aliphatic monocarboxylic acids (C3-24, e.g., acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, isocrotonic acid), and alicyclic monocarboxylic acids (C6-24, e.g., cyclohexene carboxylic acid); examples of the unsaturated poly(2-3 or more) carboxylic acids (anhydrides) include unsaturated dicarboxylic acids (anhydrides) [aliphatic dicarboxylic acids (anhydrides) (C4-24, e.g., maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and anhydrides thereof), alicyclic dicarboxylic acids (anhydrides) (C8-24, e.g., maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and anhydrides thereof), and ...9-24, e.g., maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and anhydrides thereof), and alicyclic dicarboxylic acids (anhydrides) (C10-24, e.g., maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and anhydrides thereof), and alicyclic dicarboxylic acids (anhydrides) (C12-24, e.g., maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and anhydrides thereof), and alicyclic dicarboxylic acids (anhydrides) (C14-24, e.g., maleic acid, fumaric acid, 4, for example, cyclohexene dicarboxylic acid, cycloheptene dicarboxylic acid, bicycloheptene dicarboxylic acid, methyltetrahydrophthalic acid, and anhydrides thereof, etc.], unsaturated tricarboxylic acid (anhydride) [aliphatic tricarboxylic acid (anhydride) (C5-24, for example, aconitic acid, 3-butene-1,2,3-tricarboxylic acid, 4-pentene-1,2,4-tricarboxylic acid, and anhydrides thereof), alicyclic-containing tricarboxylic acid (anhydride) (C9-24, for example, 4-cyclohexene-1,2,3-tricarboxylic acid, 4-cycloheptene-1,2,3-tricarboxylic acid, and anhydrides thereof, etc.], etc. (B) may be used alone or in combination of two or more.
Among the above (B), from the viewpoints of reactivity with the polyolefin (A) having a carbon-carbon double bond, storage stability and mechanical strength, unsaturated dicarboxylic acid anhydrides are preferred, and maleic anhydride is more preferred.

<Acid-modified polyolefin (X)>
The acid-modified polyolefin (X) in the present invention contains the polyolefin (A) and the unsaturated (poly)carboxylic acid (anhydride) (B) as constituent monomers, and is preferably obtained by reacting the polyolefin (A) with the unsaturated (poly)carboxylic acid (anhydride) (B) in the absence or presence of a radical initiator.

From the viewpoint of the balance between bundling ability and storage stability, the weight ratio of (A) to (B) [(A)/(B)] is preferably 80/20 to 99.5/0.5, and more preferably 90/10 to 99/1.

The acid-modified polyolefin (X) can be preferably produced by reacting the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly)carboxylic acid (anhydride) (B) with, as necessary, a suitable organic solvent [C3 to C18, for example, hydrocarbons (hexane, heptane, octane, dodecane, benzene, toluene, xylene, etc.), halogenated hydrocarbons (di-, tri-, and tetrachloroethane, dichlorobutane, etc.), ketones (acetone, methyl ethyl ketone, di-t-butyl ketone, etc.), ethers (ethyl-n-propyl ether, di-n-butyl ether, di-t-butyl ether, dioxane, etc.)] in the presence of a radical initiator (f).
The radical initiator (f) may be a known one, for example, an azo initiator (azobisisobutyronitrile, etc.) or a peroxide initiator (dicumyl peroxide, etc.).
Of the above (f), peroxide initiators are preferred.

From the viewpoint of reactivity between the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly)carboxylic acid (anhydride) (B) and productivity, the reaction temperature is preferably 100 to 270°C, more preferably 120 to 250°C, and particularly preferably 130 to 240°C.

The acid-modified polyolefin (X) preferably satisfies at least one of the following requirements (1) to (3), more preferably satisfies at least two, and particularly preferably satisfies all three.
(1) Acid value is 1 to 100 mgKOH/g
(2) Number average molecular weight (Mn) of 1,000 to 60,000
(3) Isotacticity of α-olefin unit chain portion is 1 to 50%

Requirement (1):
From the viewpoints of storage stability and productivity of the acid-modified polyolefin (X), the acid value of the acid-modified polyolefin (X) is preferably 1 to 100 mgKOH/g (hereinafter, only numerical values are shown), more preferably 3 to 75, and particularly preferably 5 to 50. The acid value here is a value obtained by measuring in accordance with JIS K0070 according to the following procedures (i) to (iii).
(i) 1 g of (X) is dissolved in 100 g of xylene adjusted to 100° C.
(ii) At the same temperature, titration is performed with a 0.1 mol/L ethanolic potassium hydroxide solution [product name "0.1 mol/L ethanolic potassium hydroxide solution", manufactured by Wako Pure Chemical Industries, Ltd.] using phenolphthalein as an indicator.
(iii) The amount of potassium hydroxide required for the titration is converted into mg to calculate the acid value (unit: mgKOH/g).
In the above measurement, one acid anhydride group is equivalent to one carboxyl group. The acid value in the examples described later was measured according to this method.
In addition, the acid value can be appropriately adjusted by the number of double bonds in the polyolefin (A) having a carbon-carbon double bond, the weight of the polyolefin (A) having a carbon-carbon double bond, and the type and weight of the unsaturated (poly)carboxylic acid (anhydride) (B).

Requirement (2):
From the viewpoints of mechanical strength and bundling ability, the Mn of the acid-modified polyolefin (X) is preferably from 1,000 to 60,000, more preferably from 2,000 to 50,000, and particularly preferably from 3,000 to 40,000.
In addition, the Mn of the acid-modified polyolefin (X) can be appropriately adjusted by controlling the Mn of the polyolefin (A) having a carbon-carbon double bond, the type and weight of the unsaturated (poly)carboxylic acid (anhydride) (B), and the reaction between the polyolefin (A) having a carbon-carbon double bond and the unsaturated (poly)carboxylic acid (anhydride) (B).

Requirement (3):
The isotacticity of the α-olefin unit chain portion of the acid-modified polyolefin (X) is preferably 1 to 50%, more preferably 5 to 45%, and particularly preferably 10 to 40%, from the viewpoints of bundling ability and storage stability.
Furthermore, the isotacticity of the α-olefin unit chain portion of the acid-modified polyolefin (X) can be appropriately adjusted by the isotacticity of the polyolefin (A) having a carbon-carbon double bond and the high molecular weight polyolefin (A0) as described above.

<(Partial) neutralized product (XC)>
The (partially) neutralized product (XC) in the present invention is a (partially) neutralized product of the acid-modified polyolefin (X) and a base (C) described below.

The neutralization rate (%) of the neutralized product (XC) is preferably from 10 to 100%, more preferably from 20 to 90%, and particularly preferably from 30 to 80%, from the viewpoints of storage stability and mechanical strength.
The neutralization rate (%) means the number of moles (mol %) of the base (C) relative to the number of moles of carboxyl groups in the acid-modified polyolefin (X), and can be calculated from the acid value of the acid-modified polyolefin (X) and its weight, and the base value (alkali value) (mg KOH/g) of the base (C) and its weight.
In addition, when the acid group is a carboxylic anhydride group, the acid value is measured assuming that one acid anhydride group is equivalent to one carboxyl group, and therefore the obtained acid value is doubled to calculate the neutralization rate.

<Base (C)>
The base (C) in the present invention is preferably a monovalent base, for example, a monoamine {for example, monoalkylamines (methylamine, ethylamine, etc.) in which the alkyl group has 1 to 10 carbon atoms, dialkylamines (dimethylamine, diethylamine, methylethylamine, etc.) in which the alkyl group has 1 to 10 carbon atoms, trialkylamines (for example, trimethylamine, triethylamine, trimethylamine, dimethylbutylamine, etc.) in which the alkyl group has 1 to 10 carbon atoms, aminoalcohols (for example, ethanolamine, propanolamine, isopropanolamine, diethanolamine, trimethanolamine, triethanolamine, tripropanolamine, dimethylaminoethanol, dimethylaminopropanol, etc.) in which the alkyl group has 1 to 30 carbon atoms, heterocyclic amines (for example, morpholine, etc.), etc.}, ammonia, hydroxides of alkali metals (sodium hydroxide, potassium hydroxide, etc.), and the like.
Of the above bases (C), from the viewpoint of sizing ability, monoamines and ammonia are preferred, trialkylamines (wherein the alkyl groups each independently have 1 to 4 carbon atoms) are more preferred, and triethylamine is particularly preferred.

<Multifunctional amine (am)>
The polyfunctional amine (am) in the present invention is preferably an amine having at least two primary and/or secondary amino groups, and examples thereof include polyalkylene polyamines (for example, those having an alkylene group with 1 to 20 carbon atoms, specific examples being ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc.), polyallylamine (PAA series manufactured by Nittobo Corporation, etc.), polyethyleneimine (Epomin series manufactured by Nippon Shokubai Co., Ltd., etc.), and terminal amino group-modified polyalkylene glycols (Chemistat Y-400 manufactured by Sanyo Chemical Industries, Ltd., etc.).
Among the above (am), polyallylamine and polyethyleneimine are preferred from the viewpoints of bundling ability and mechanical strength.

The total (mg KOH/g) of the primary amine value and secondary amine value of the polyfunctional amine (am) is preferably 250 to 1,200, more preferably 300 to 1,100, and particularly preferably 500 to 1,000, from the viewpoints of mechanical strength and sizing ability.
The sum of the primary amine value and the secondary amine value can be calculated from the difference between the total amine value and the tertiary amine value (total amine value - tertiary amine value). The total amine value is measured by the method of ASTM D2074. However, chloroform is used as the solvent for dissolving the sample, and a 0.1 mol/L perchloric acid acetic acid standard solution is used as the titration solution.
The tertiary amine value refers to the amount of potassium hydroxide (mg) equivalent to the amount of perchloric acid required to neutralize the tertiary amine contained in 1 g of a sample, and is measured by the following method in accordance with ASTM D2073.
(1) Accurately weigh the sample. [Sample amount: S (g)]
(2) Add 20 mL of a mixed solution of acetic anhydride/acetic acid (9/1) to dissolve, and allow to stand at room temperature for 3 hours.
(3) Add 30 mL of acetic acid and titrate with a 0.1 mol/L perchloric acid/acetic acid solution (titer: f) using a potentiometric titrator. [Titer: A (mL)]
(4) Perform a blank test in the same manner as above. [Titer amount: B (mL)]
(5) Calculate the tertiary amine value using the following formula.
Tertiary amine value = (A - B) x f x 0.1 x 56.108 / S

From the viewpoint of mechanical strength and bundling ability, the weight average molecular weight (Mw) of the polyfunctional amine (am) is preferably 1,000 to 75,000, more preferably 1,500 to 50,000, and particularly preferably 3,000 to 30,000.

The polyfunctional amine (am) may be neutralized with an acid (ac). Examples of the acid (ac) include monovalent acids (hydrochloric acid, acetic acid, nitric acid, etc.), divalent acids (sulfuric acid, etc.), and trivalent acids (phosphoric acid, etc.). Of these, from the viewpoint of mechanical strength, monovalent acids are preferred, and hydrochloric acid and acetic acid are more preferred. The neutralization rate is not particularly limited, but is preferably 0 to 100%, and more preferably 0 to 80%.

<Aqueous composition (Y)>
The aqueous composition (Y) of the present invention comprises an aqueous medium, the (partially) neutralized product (XC), and the polyfunctional amine (am).
From the viewpoint of storage stability, the (partially) neutralized product (XC) is preferably contained in the aqueous composition (Y) in the form of particles.
From the viewpoint of sizing ability, the aqueous composition (Y) is preferably a mixture of an aqueous dispersion (D) in which the (partially) neutralized product (XC) is dispersed in an aqueous medium and a polyfunctional amine (am). It is preferable that the composition is:
The aqueous composition (Y) can be used for various applications, but can be suitably used in particular as a sizing agent for inorganic fibers, and further as a sizing agent for carbon fibers.
The aqueous medium includes water and aqueous solvents (having a solubility in water of 10 g or more/100 g water at 25° C.).
Examples of the aqueous solvent include ketones (acetone, methyl ethyl ketone (hereinafter abbreviated as MEK), diethyl ketone, etc.), alcohols (methanol, ethanol, isopropanol, etc.), etc., which are preferable from the viewpoint of productivity of the aqueous composition (Y). The aqueous solvents are acetone, MEK and isopropanol. One or more of the aqueous solvents may be used.
Of the above aqueous media, from the viewpoint of working environment, water is preferably 70% by weight or more, more preferably 95% by weight or more, and most preferably water.

The aqueous composition (Y) can be produced, for example, by the following method.
(1) An acid-modified polyolefin (X), a base (C), and an aqueous solvent are charged and mixed, and then water is charged while stirring, phase inversion emulsification is performed, and if necessary, the aqueous solvent is distilled off to obtain an aqueous dispersion (D) in which (XC) is dispersed in an aqueous medium. A polyfunctional amine (am) (preferably an aqueous solution) is added to this to obtain an aqueous composition (Y).
(2) An acid-modified polyolefin (X), a base (C), and water are mixed, and the mixture and an aqueous medium are dispersed by a disperser to obtain an aqueous dispersion (D) in which (XC) is dispersed in the aqueous medium. A polyfunctional amine (am) (preferably an aqueous solution) is added to the aqueous dispersion to obtain an aqueous composition (Y).
Of the above (1) and (2), from the viewpoints of industrial application and storage stability, (1) is preferred.
In addition, in the step of obtaining the aqueous dispersion, in addition to the acid-modified polyolefin (X), the base (C), and the polyfunctional amine (am), a publicly known anionic surfactant, cationic surfactant, amphoteric surfactant, or nonionic surfactant (for example, emulsifier (F) described in JP2015-131889A) may be used as necessary.

In the above aqueous composition (Y), the weight ratio of the (partially) neutralized product (XC) to the polyfunctional amine (am) [(XC)/(am)] is preferably 20/80 to 80/20, more preferably 30/70 to 70/30, and particularly preferably 40/60 to 60/40, from the viewpoints of sizing ability and mechanical strength.

The total weight of the (partially) neutralized product (XC) and the polyfunctional amine (am) based on the weight of the aqueous composition (Y) is preferably 5 to 50% by weight, more preferably 10 to 45% by weight, and still more preferably 15 to 40% by weight, from the viewpoints of industrial application and storage stability.
From the viewpoint of cost, etc., it is preferable that the aqueous composition (Y) of the present invention has a high concentration as described above when distributed and a low concentration (e.g., 0.05 to 5% by weight, etc.) when producing inorganic fiber bundles. That is, by distributing it at a high concentration, transportation costs and storage costs can be reduced, and by treating the fibers at a low concentration, inorganic fiber bundles that impart excellent molded body strength can be produced.

The volume-based median diameter (median particle diameter) of the (partially) neutralized product (XC) in the aqueous composition (Y) is preferably 0.05 to 5 μm, more preferably 0.1 to 2.5 μm, from the viewpoints of storage stability and focusing. The median diameter can be measured using a laser diffraction particle size distribution measuring device.

<Inorganic fiber bundle>
The inorganic fiber bundle of the present invention is obtained by treating inorganic fibers with an inorganic fiber sizing agent [the aqueous composition (Y) of the present invention]. In a preferred embodiment, the inorganic fiber bundle is obtained by treating carbon fibers with a carbon fiber sizing agent [the aqueous composition (Y) of the present invention].

Examples of inorganic fibers include known fibers such as carbon fibers, glass fibers, aramid fibers, ceramic fibers, metal fibers, mineral fibers, rock fibers, and slag fibers (such as those described in International Publication No. 2003/47830), and from the viewpoint of the strength of the molded body (fiber-reinforced composite material), carbon fibers are preferred. Two or more of these fibers may be used in combination.

The inorganic fiber bundle of the present invention is obtained by treating the inorganic fibers using the aqueous composition (Y) of the present invention as an inorganic fiber sizing agent, and is preferably an inorganic fiber bundle in which approximately 3,000 to 50,000 inorganic fibers are bundled together.
For example, a carbon fiber bundle is obtained by treating carbon fibers using the aqueous composition (Y) of the present invention as a carbon fiber sizing agent, and is preferably a carbon fiber bundle in which approximately 3,000 to 50,000 carbon fibers are bundled together.

Methods for treating the inorganic fibers include a spray method, a dipping method, and the like.
Specifically, the inorganic fiber sizing agent is diluted in an aqueous medium to prepare an aqueous diluted solution (S) of the inorganic fiber sizing agent having a weight percentage of solids of 0.05 to 5% by weight, and the inorganic fibers are sprayed with (S) or immersed in (S) and dried to adhere the solids to the inorganic fibers.
In the inorganic fiber bundle, the adhesion amount, which is the weight of the solid content in the inorganic fiber bundling agent on the inorganic fibers, is preferably 0.05 to 5% by weight, more preferably 0.2 to 3.0% by weight, based on the weight of the inorganic fibers. This range is preferable because it improves the strength of the molded product.
The solid content herein refers to the residue remaining after 1 g of the sample is dried by heating at 130° C. for 45 minutes in a circulating air dryer.

<Complex intermediate>
The composite intermediate of the present invention contains the inorganic fiber bundle of the present invention and a matrix resin. The matrix resin may be a thermoplastic resin (e.g., polyolefin resin such as polypropylene resin, polyamide resin, polyester resin, polycarbonate resin, polyphenylene sulfide resin, etc.) or a thermosetting resin (epoxy resin, unsaturated polyester resin (e.g., those described in Japanese Patent No. 3723462, etc.), vinyl ester resin, phenol resin (e.g., those described in Japanese Patent No. 3723462, etc.)), etc.), preferably a polyolefin resin, and more preferably a polypropylene resin.

The composite intermediate of the present invention may contain a modifier as necessary. When a modifier is contained, the strength of the molded product is further improved. Examples of modifiers include acid-modified polyolefins (e.g., product name "UMEX 1001" manufactured by Sanyo Chemical Industries, Ltd.).

The weight ratio of the matrix resin to the inorganic fiber bundles (matrix resin/inorganic fiber bundles) is preferably 10/90 to 90/10, more preferably 20/80 to 50/50, and particularly preferably 20/80 to 40/60, from the viewpoint of molded body strength, etc. When a modifier is contained, the content (wt%) of the modifier relative to the matrix resin is preferably 0.1 to 50, more preferably 1 to 20, and particularly preferably 3 to 10, from the viewpoint of molded body strength, etc.

<Fiber-reinforced composite materials>
The fiber-reinforced composite material of the present invention is obtained by molding the composite intermediate. When the matrix resin is a thermoplastic resin, the composite intermediate can be heated and molded, and solidified at room temperature to form a molded product. The method of heat molding is not particularly limited, and examples thereof include a filament winding molding method (a method of winding a composite intermediate sheet around a rotating mandrel under tension and heat molding it), a press molding method (a method of stacking composite intermediate sheets and heat molding it), an autoclave method (a method of pressing a composite intermediate sheet against a mold with pressure and heat molding it), and a method of mixing chopped fibers or milled fibers with a matrix resin and injection molding it.
INDUSTRIAL APPLICABILITY The fiber-reinforced composite material of the present invention has excellent mechanical strength and can therefore be widely used in applications such as automobiles, aircraft, and electronic devices.

The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, % means % by weight and parts means parts by weight. In the following, Examples 6 to 8 and 10 are Reference Examples 1 to 4, respectively.

<Production Example 1>
A reaction vessel was charged with 1,000 g of a polyolefin (A0-1) having structural units of 85% propylene and 15% ethylene [trade name "Vistamaxx 6202", manufactured by Exxon Mobil, the same applies below], which was heated and melted using a mantle heater while passing nitrogen through the gas phase, and thermally degraded at 380° C. for 50 minutes with stirring, to obtain a polyolefin (A-1) having a carbon-carbon double bond.
The polyolefin (A-1) had an Mn of 3,900, the number of double bonds at the molecular terminals and/or in the molecular chain per 1,000 carbons was 7.4, and the isotacticity was 17%.

<Production Examples 2 to 9, Comparative Production Examples 1 to 2>
Polyolefins (A) having each carbon-carbon double bond were obtained in the same manner as in Production Example 1, except for following Table 1. The results are shown in Table 1.

<Production Example 11>
A reaction vessel was charged with 100 parts of (A-1) and 5 parts of maleic anhydride (B-1), and after replacing with nitrogen, the mixture was heated to 180°C under nitrogen aeration to dissolve uniformly. A solution of 2 parts of a radical initiator [dicumyl peroxide, trade name "Percumyl D", manufactured by NOF Corp.] (f-1) dissolved in 5 parts of xylene was added dropwise thereto over 5 minutes, and stirring was continued for 1 hour under xylene reflux. Thereafter, unreacted maleic anhydride was distilled off under reduced pressure (1.5 kPa, the same applies below) to obtain an acid-modified polyolefin (X-1).
Incidentally, (X-1) had an acid value of 26, an Mn of 4,500, and an isotacticity of 14%.

<Production Examples 12 to 21, Comparative Production Examples 11 to 12>
Each acid-modified polyolefin (X) was obtained in the same manner as in Production Example 11, except for following Table 2. The results are shown in Table 2.

Example 1
In a reaction vessel equipped with a stirrer, a heating/cooling device, and a thermometer, 100 parts of (X-1), 4.5 parts of triethylamine (C-1) [manufactured by Tokyo Chemical Industry Co., Ltd.], and 80 parts of tetrahydrofuran were charged, and the mixture was uniformly dissolved at 60° C. under stirring. 233 parts of water was gradually added over 5 hours to carry out phase inversion emulsification.
After cooling to room temperature, tetrahydrofuran was removed under reduced pressure, and water was added so that the solid content was 30.0% by weight, to obtain an aqueous dispersion (D-1) containing the (partially) neutralized product (XC-1).
Further, with stirring, 500 parts of a 15% aqueous solution of polyallylamine (Mw: 15,000) (am-1) [trade name "PAA-15C", Nittobo Medical Co., Ltd., with the concentration adjusted] was added over 1 hour to obtain an aqueous composition (Y-1).

<Examples 2 to 14, Comparative Examples 1 and 2>
Each aqueous composition (Y) was obtained in the same manner as in Example 1, except that the raw material composition (parts) in Table 3 was used.
Each of the aqueous compositions (Y) thus obtained was evaluated by the evaluation methods described below. The results are shown in Table 3.

The average particle size (median size) was measured using a laser diffraction particle size distribution analyzer "LA-750" (manufactured by Horiba, Ltd.).

<1> Storage stability of aqueous composition (Y) 30 g of aqueous composition (Y) was placed in a screw tube bottle [50 mL (body diameter 35 mm × height 78 mm)] and stored for 14 days at 30° C. From the measurement results of the median diameter (μm) before and after storage, the storage stability at 30° C. was calculated using the following calculation formula and evaluated according to the following evaluation criteria.
(Storage stability) (%) =
(Median diameter after storage) × 100 / (Median diameter before storage)

<Evaluation criteria>
☆: Less than 105% ◎: 105% or more, less than 110% ○: 110% or more, less than 115% △: 115% or more, less than 120% ×: 120% or more

<2> Bundling ability of inorganic fibers Each aqueous composition (Y) was diluted with water so that the solid content was 3%, to obtain a diluted solution. Carbon fibers (number of filaments = 12,000) were immersed in the diluted solution to be impregnated, and then dried at 170 ° C for 180 seconds to obtain a carbon fiber bundle (adhesion amount: 1 wt %). The bundling ability of the carbon fiber bundle was evaluated according to the following evaluation criteria in accordance with JIS L1096-1999 (8.19.1A method, 45 degree cantilever method).

<Evaluation criteria>
☆: 15 cm or more ◎: 14 cm or more, less than 15 cm ○: 13 cm or more, less than 14 cm △: 12 cm or more, less than 13 cm ×: Less than 12 cm

<3> Fluff of inorganic fiber bundle Five chrome-plated stainless steel rods with a diameter of 2 mm were arranged in a zigzag pattern at 15 mm intervals so that the carbon fiber bundle obtained in <2> above passed over the surface of the rods while contacting the rods at a contact angle of 120°. The carbon fiber bundle was hung between the stainless steel rods in a zigzag pattern and subjected to a tension of 1 kg. Just before the take-up roll, the carbon fiber bundle was sandwiched between two 10 cm x 10 cm urethane foam sheets with a load of 1 kg, and rubbed for 5 minutes at a speed of 1 m/min. The weight of the fluff attached to the sponge during this time was measured and evaluated according to the following criteria.

<Evaluation criteria>
☆: Less than 0.05 mg/m ◎: 0.05 mg/m or more, less than 0.10 mg/m ○: 0.10 mg/m or more, less than 0.20 mg/m △: 0.20 mg/m or more, less than 0.30 mg/m ×: 0.30 mg/m or more

<4> Bending strength of fiber reinforced composite material A matrix resin was prepared by melt-kneading 95 parts by weight of "Sunallomer PL500A" [polypropylene, manufactured by Sunallomer Co., Ltd.] and 5 parts by weight of "UMEX 1001" [maleic anhydride modified polypropylene, acid value 26, manufactured by Sanyo Chemical Industries, Ltd.], and melt-impregnating the resulting carbon fiber bundles to 30% by weight and 70% by weight of the matrix resin. The carbon fiber bundles were cut into 5 mm pieces using a pelletizer and then uniformly mixed at 200°C to obtain a composite intermediate. The fiber reinforced composite material was press-molded to measure bending strength in accordance with JIS K7074 (bending test method for carbon fiber reinforced plastics) and evaluated according to the following evaluation criteria.

<Evaluation criteria>
☆: 280 MPa or more ◎: 260 MPa or more, less than 240 MPa ○: 240 MPa or more, less than 220 MPa △: 220 MPa or more, less than 240 MPa ×: less than 220 MPa

The results in Tables 1 to 3 show that the aqueous composition (Y) of the present invention has superior storage stability, bundling of inorganic fibers, and less fuzzing of fiber bundles compared to the comparative compositions. It is also found to provide superior mechanical strength to fiber-reinforced composite materials.

The aqueous composition (Y) of the present invention can be used for various purposes, but is particularly suitable as an inorganic fiber bundling agent, and further as a bundling agent for carbon fibers. When used as an inorganic fiber bundling agent, it is extremely useful because it has excellent bundling properties and provides excellent mechanical strength to fiber-reinforced composite materials, and can be widely used in applications such as automobiles, aircraft, and electronic devices.

Claims (10)

The aqueous composition (Y) is an inorganic fiber sizing agent comprising an aqueous medium, a (partial) neutralization product (XC) of an acid-modified polyolefin (X) and a base (C), and a polyfunctional amine (am), the (X) comprising, as constituent raw materials, a polyolefin (A) having a carbon-carbon double bond and an unsaturated (poly)carboxylic acid (anhydride) ( B), the polyolefin (A) comprising only ethylene and propylene as constituent monomers, the weight ratio of the ethylene to the propylene [ethylene/propylene] being 10/90 to 30/70, and the acid value of the acid-modified polyolefin (X) being 15 to 46 mgKOH/g. The aqueous composition according to claim 1, wherein the polyolefin (A) has 0.5 to 20 carbon-carbon double bonds per 1,000 carbon atoms. 3. The aqueous composition according to claim 1, wherein the acid-modified polyolefin (X) has a number average molecular weight (Mn) of 1,000 to 60,000. 4. The aqueous composition according to claim 1, wherein the isotacticity of the α-olefin unit chain portion of the polyolefin (X) is 1 to 50%. 5. The aqueous composition according to claim 1, wherein the base (C) is a trialkylamine (wherein the alkyl groups each independently have 1 to 4 carbon atoms). The aqueous composition according to any one of claims 1 to 5, wherein the neutralization rate of the (partially) neutralized product (XC) is 10 to 100%. The aqueous composition according to any one of claims 1 to 6, wherein the weight ratio of the (partially) neutralized product (XC) to the polyfunctional amine (am) [(XC)/(am)] is 20/80 to 80/20. An inorganic fiber bundle, which is an inorganic fiber treated with the aqueous composition (Y) according to any one of claims 1 to 7 . A composite intermediate comprising the inorganic fiber bundles according to claim 8 and a matrix resin. A fiber-reinforced composite material formed by molding the composite intermediate product according to claim 9 .