JP5988771B2 - Method for producing aqueous polyamide resin dispersion - Google Patents

Description

  The present invention relates to a method for producing a polyamide resin aqueous dispersion, a fiber treatment agent using the polyamide resin aqueous dispersion obtained by the production method, and a fiber or fiber composite material obtained by treatment with the fiber treatment agent. .

  Aqueous dispersion of polyamide resin is coated on a base material to form a coating film of polyamide resin, giving oil resistance, solvent resistance, chemical resistance, abrasion resistance, gas barrier properties, adhesion, etc. Water-based inks, fiber sealants, glass fiber sizing agents, paper treatment agents, binders, lubricants, steel sheet surface treatment agents, surface modifiers, interlining adhesives and other hot melt adhesives, etc. Widely used. One of the uses of such an aqueous dispersion of polyamide resin is a treating agent for fibers.

  There are many types of fibers, and their uses vary from home clothing to the field of space science, contributing to the development of industry in various forms. For example, the fibers can be broadly divided into natural fibers obtained from plants and animals, synthetic fibers obtained by synthesizing organic chemicals, semi-synthetic fibers, organic fibers such as regenerated fibers, acrylic fibers or pitch as raw materials at high temperatures. Inorganic fibers such as carbon fibers, glass fibers, metal fibers and rock fibers produced by carbonization are known.

  When these fibers are used industrially, they are often used with a treatment agent. The functions of the treatment agent are also diverse, and it is used to adjust the shape of the fiber, to make the fiber flexible, and to facilitate the fiber processing process, and to the fiber for strength, flexibility, heat resistance, weather resistance There are those used for imparting high functions such as anti-slip, anti-slip, antistatic and antibacterial properties. Generally, fiber treatment agents are often used in a liquid form. A solution type fiber treatment agent in which a resin is dissolved in a solution and an aqueous dispersion type fiber treatment agent in which the resin is dispersed in water are used. However, the aqueous dispersion type can form a film having excellent heat resistance and strength when the fiber treatment agent is dried and the liquid is removed by vaporization compared to the solution type. Since it is easy, the physical strength of the fiber can be improved. In addition, the obtained film can be used as a binder to have good adhesion to various matrix resins.

  In particular, when an aqueous dispersion of polyamide resin is used as a treating agent for fibers, the excellent properties of polyamide resin are used to improve the physical strength and adhesion of fibers, as well as oil resistance, solvent resistance, and chemical resistance. The fiber can have functions such as wear resistance and gas barrier properties. In addition, since the polyamide resin is excellent in compatibility with various thermoplastic resins, it can be suitably used for producing a fiber composite material using a thermoplastic resin as a matrix resin.

  There are several examples of an aqueous dispersion of polyamide resin that can be used as such a treating agent for fibers. For example, in Patent Document 1 below, in order to improve yellowing and mechanical stability, A method of blending an aqueous dispersion with a basic substance, an ammonia compound or the like is described, and the following Patent Document 2 describes the crosslinking of an epoxy compound or the like with an aqueous dispersion of polyamide resin in order to improve the adhesive strength of the aqueous dispersion. A method of blending the agent is described.

  However, the aqueous dispersion of polyamide resin depends on the type of polyamide resin, but has a drawback that it is relatively unstable and difficult to handle as compared with aqueous dispersions of other general-purpose resins. The change in viscosity is large, and there are many points where it is difficult to optimize the production conditions. Even the methods according to Patent Documents 1 and 2 have not been able to solve the problem so much in terms of stability.

  This is because the polyamide resin has a strong polar amide bond in the molecule, and also has an ionic functional group such as a carboxyl group and an amino group, so that the particles exhibit a complex electrolyte behavior in water. It is presumed to be caused by In order to improve the stability of such an aqueous dispersion of polyamide resin, Patent Document 3 below describes a method for improving stability by using an amino acid and a surfactant in combination.

  However, although the stability of the aqueous polyamide resin dispersion obtained by the method of Patent Document 3 is slightly improved, the adhesiveness is inferior, and there is room for further improvement for use as a fiber treating agent.

JP 2005-105192 A JP 2005-126562 A JP-T 6-509824

  An object of the present invention is to provide a method for producing an aqueous polyamide resin dispersion having excellent stability such as little change in viscosity over time. Another object of the present invention is to provide a fiber treating agent having excellent adhesiveness, including the aqueous polyamide resin dispersion obtained by the production method. Another object of the present invention is to provide a fiber or fiber composite material obtained using the fiber treating agent.

  As a result of intensive studies to achieve the above-described object, the present inventor stirs a polyamide resin dispersion having a specific composition and a specific viscosity under specific agitation conditions. It has been found that an aqueous polyamide resin dispersion excellent in stability such as a small amount can be obtained. Further, the obtained aqueous dispersion of polyamide resin makes it possible to obtain a fiber composite material having excellent adhesion between the fiber and the matrix resin when used as a fiber treating agent. The present invention has been completed by finding that a fiber composite material with good mechanical properties can be obtained.

That is, the present invention encompasses the subject matters described in the following sections.
Item 1.
Including a polyamide resin, a basic substance, a polymer dispersant and an aqueous medium,
A polyamide resin dispersion raw material liquid having a viscosity at 25 ° C. and 60 rpm in a B-type rotary viscometer of 300 mpa · s or more,
With the internal insertion type agitator, the tip peripheral speed of the agitator blade is 10 m / s or more and the number of passes P1 defined by the following formula (1) is 20 times or more, or
A polyamide resin aqueous dispersion which is stirred by a continuous circulation processing type stirrer at a tip peripheral speed of the stirrer blade of 10 m / s or more and a pass number P2 defined by the following formula (2) of 1 or more. Manufacturing method.
Formula (1)
Number of passes P1 = Q x stirring time (min) / total liquid volume (L)
Here, Q indicates the discharge amount [L / min] and is represented by the following equation.
^{Q = Nq · n · d 3} /1000
Nq: discharge coefficient n: stirring blade rotation speed [rpm] d: stirring blade diameter [cm]
Formula (2)
Number of passes P2 = Flow rate (L / min) x Agitation time (min) / Total liquid volume (L)
Item 2.
Item 2. The method for producing an aqueous dispersion of polyamide resin according to Item 1, wherein the stirrer is a rotary shear type stirrer.
Item 3.
The polyamide resin dispersion raw material liquid is
A mixed liquid containing a polyamide resin, a basic substance, a polymer dispersant, and an aqueous medium is an emulsion obtained by stirring and emulsifying at a temperature higher than the softening temperature of the polyamide resin.
Item 3. A method for producing an aqueous polyamide resin dispersion according to Item 1 or 2.
Item 4.
Item 4. The method for producing an aqueous polyamide resin dispersion according to any one of Items 1 to 3, wherein the polymer dispersant is at least one selected from the group consisting of polyvinyl pyrrolidone, polyethylene glycol, and an ethylene oxide / propylene oxide copolymer.
Item 5.
In the polyamide resin dispersion raw material liquid,
Item 5. The method for producing an aqueous polyamide resin dispersion according to any one of Items 1 to 4, wherein the polymer dispersant is contained in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyamide resin.
Item 6.
Item 6. A treating agent for fibers comprising an aqueous polyamide resin dispersion obtained by the production method according to any one of items 1 to 5.
Item 7.
Item 7. The fiber treatment agent according to Item 6, wherein the fiber treatment agent is a carbon fiber treatment agent.
Item 8.
Item 8. A method for producing a fiber or a fiber composite material treated with a fiber treating agent by treating the fiber with the fiber treating agent according to Item 6 or 7.

  According to the method for producing a polyamide resin aqueous dispersion of the present invention, it is possible to obtain a polyamide resin aqueous dispersion excellent in stability, such as little change in viscosity over time. Further, the fiber treatment agent containing the aqueous polyamide resin dispersion has excellent adhesion, and when the fiber treatment agent is used, a fiber composite material having excellent adhesion between the fiber and the matrix resin can be obtained. .

  Hereafter, the manufacturing method of the polyamide resin aqueous dispersion of this invention is demonstrated in detail.

  The method for producing a polyamide resin aqueous dispersion of the present invention is characterized in that a polyamide resin dispersion having a specific composition and a specific viscosity is stirred under specific stirring conditions. In this specification, the polyamide resin dispersion having a specific composition and specific viscosity before stirring is referred to as a polyamide resin dispersion raw material liquid for convenience.

The polyamide resin-dispersed raw material liquid has a viscosity of not less than 300 mpa · s at 25 ° C. and 60 rpm in a B-type rotary viscometer. (Hereinafter, the viscosity means the viscosity at 25 ° C. and 60 rpm in a B-type rotary viscometer unless otherwise specified.)
The polyamide resin dispersion raw material liquid contains a polyamide resin, a basic substance, a polymer dispersant, and an aqueous medium.

  The method for producing the polyamide resin-dispersed raw material liquid is not particularly limited as long as the polyamide resin-dispersed raw material liquid having the above specific viscosity and specific composition can be produced. Viscosity adjustment in emulsion liquid obtained by emulsifying polyamide resin using surfactant, etc., a method of dispersing polyamide resin powder obtained by pulverization by a pulverization method in an aqueous medium so as to have a predetermined viscosity And a method of neutralizing the terminal carboxyl group in the polyamide resin with a basic substance and self-emulsifying to prepare an emulsion. In addition, a basic substance and a polymer dispersing agent can be appropriately added according to the selected production method.

  In the present invention, from the viewpoint of easy adjustment of the viscosity, in particular, when the terminal carboxyl group in the polyamide resin is neutralized with a basic substance and self-emulsified to produce an emulsion, the basic substance is used. A method for producing a polyamide resin-dispersed raw material liquid is preferably used by adjusting the amount of the above and adjusting the viscosity to 300 mpa · s or more. Hereinafter, an embodiment of this method will be described in detail.

  In one embodiment of this method, first, a polyamide resin, a basic substance, a polymer dispersant, and an aqueous medium are charged into a container to prepare a mixed solution thereof.

  As a container used for the preparation of the mixed solution, a container provided with stirring means capable of uniformly mixing the contents is preferable. Moreover, the container provided with the heating means for heating to the temperature more than the temperature which a polyamide resin softens in an aqueous medium is preferable. A pressure vessel is preferred. A container having two or all of these conditions is particularly preferable. For example, a pressure-resistant autoclave with a stirrer is particularly preferable.

  Next, the mixed solution is heated to a temperature higher than the softening temperature of the polyamide resin and stirred to emulsify the mixed solution. By cooling the emulsion thus obtained to room temperature, a polyamide resin dispersion raw material liquid having a viscosity of 300 mpa · s or more is obtained. The above is one aspect of a suitable method for producing a polyamide resin-dispersed raw material liquid.

  As the polyamide resin used in the present invention, a commercially available product may be used, or an appropriately manufactured product may be used.

  A known method is used as a method for producing the polyamide resin. For example, methods such as polycondensation of diamine and dicarboxylic acid, polycondensation of ω-amino-ω ′ carboxylic acid, or ring-opening polymerization of cyclic lactam can be mentioned. Here, dicarboxylic acid or monocarboxylic acid can be used as a polymerization regulator in the polycondensation or ring-opening polymerization.

  Specific examples of the diamine include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diamino. Examples include decane, phenylenediamine, and metaxylylenediamine.

  Specific examples of dicarboxylic acids include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, tetradecanedicarboxylic acid, octadecanedicarboxylic acid, fumaric acid, phthalic acid, xylylene diene Examples thereof include carboxylic acids and dimer acids (unsaturated dicarboxylic acids having 36 carbon atoms synthesized from unsaturated fatty acids mainly composed of linoleic acid or oleic acid).

  Specific examples of the ω-amino-ω ′ carboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid.

  Specific examples of the cyclic lactam include ε-caprolactam, ω-enantolactam, and ω-lauryl lactam.

Specific examples of the dicarboxylic acid used as the polymerization regulator include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and nonanedicarboxylic acid, as well as the dicarboxylic acid used in the production of the polyamide resin. Examples include acid, decanedicarboxylic acid, tetradecanedicarboxylic acid, octadecanedicarboxylic acid, fumaric acid, phthalic acid, xylylene dicarboxylic acid, and dimer acid. Specific examples of the monocarboxylic acid include caproic acid, heptanoic acid, nonanoic acid, undecanoic acid, and dodecanoic acid.

In the present invention, among the polyamide resins obtained by the above method, in particular, — [NH (CH ₂ ) ₅ CO] —, — [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO] —, — [ _{NH (CH 2) 6 NHCO (} CH 2) 8 CO] -, - [NH (CH 2) 10 CO] -, - [NH (CH 2) 11 CO] - and _{- [NH (CH 2) 2} NHCO- A polyamide resin having at least one selected from the group consisting of D—CO] — (wherein D represents an unsaturated hydrocarbon having 34 carbon atoms) as a structural unit is preferably used.

Specific examples thereof include 6-nylon, 66-nylon, 610-nylon, 11-
Nylon, 12-nylon, 6/66 copolymer nylon, 6/610 copolymer nylon, 6 /
11 copolymer nylon, 6/12 copolymer nylon, 6/66/11 copolymer nylon, 6/6
6/12 copolymer nylon, 6/66/11/12 copolymer nylon, 6/66/610/1
Examples thereof include 1/12 copolymer nylon and dimer acid polyamide resins, and polyamide elastomers that are copolymers of these copolymer nylons with polyesters and polyalkylene ether glycols. “/” Is a symbol used to indicate that it is a copolymer of each nylon. For example, 6/66 copolymer nylon represents a copolymer nylon of 6-nylon and 66-nylon.

  Furthermore, as an example of the polyamide resin used in the present invention, dimer acid-based polyamide and polyamide elastomer are also exemplified. Specific examples of the polyamide elastomer include polyamide elastomers that are a copolymer of nylon and polyester, or a copolymer of nylon and polyalkylene ether glycol. Examples of the polyalkylene ether glycol include polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol, polyhexamethylene oxide glycol and the like. Examples of the polyester include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polytrimethylene naphthalate, and polybutylene naphthalate.

  Polyamides can be used alone or in combination of two or more.

  The polyamide-based elastomer is not particularly limited, but a block copolymer including a polyamide block and a polyether block is preferable. In particular, a block copolymer having a structure in which polyamide and polyether are copolymerized is preferable, and a block copolymer having a structure in which polyamide and polyether are copolymerized is particularly preferable. Examples of the constituent component of the polyether block include glycol compounds such as polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol, and polyhexamethylene oxide glycol, and diamine compounds such as polyether diamine. Two or more of these components may be used. As such a polyamide elastomer, there are several types having different molecular structures at the bonding part between the polyamide block and the polyether block, that is, bonding forms, for example, “(polyamide block) —CO—NH— (polyether block)”. Examples thereof include a polyether block amide copolymer having a bonding form, a polyether ester block amide copolymer having a bonding form of “(polyamide block) -CO—O— (polyether block)”, and the like.

  Polyamide elastomers are known or can be easily produced by known methods. For example, after reacting at least one of a lactam compound, an aminocarboxylic acid compound, and a diamine compound with a dicarboxylic acid to prepare a polyamide block substantially having both carboxyl groups at both ends, the polyamide block is coated with polyethylene oxide glycol. The method of making it react by adding and heating diamine compounds, such as glycol compounds or polyether diamine, etc. can be mentioned. Moreover, a commercial item can also be purchased and used. Examples of commercially available products include a polyether block amide copolymer (trade name “UBESTAXPA9044X2”) manufactured by Ube Industries, Ltd., and a polyether ester block amide copolymer (trade name “Pebax 2533SA01”) manufactured by Arkema. Can do.

  Although not intended to be limited in interpretation, when the polyamide-based elastomer is a block copolymer comprising a polyamide block and a polyether block, a hard polymer portion having a polyamide block (also referred to as a hard segment) And a soft polymer portion having a polyether block (also referred to as a soft segment).

  Although it does not specifically limit as a basic substance used for this invention, For example, alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide, ammonia, an amine compound, etc. are mentioned. Among these, sodium hydroxide or potassium hydroxide is particularly preferably used from the viewpoint of excellent stationary stability of the aqueous polyamide resin dispersion. A basic substance can be used by 1 type or in combination of 2 or more types.

  The basic substance has little change in the viscosity of the obtained aqueous polyamide resin dispersion over time, or has excellent adhesion between the fiber and the matrix resin when the obtained aqueous polyamide resin dispersion is used as a fiber treatment agent, etc. From this point of view, the polyamide resin-dispersed raw material is preferably such that the valence of the base is preferably 0.1 mol or more, more preferably 0.4 mol or more with respect to 1 mol of the terminal carboxyl group of the polyamide resin. Contained in the liquid. Further, it is preferably contained in the polyamide resin dispersion raw material liquid so as to be 2 mol or less, more preferably 1.5 mol or less. Furthermore, it is contained in the polyamide resin dispersion raw material liquid so as to be preferably 0.1 to 2 mol, more preferably 0.4 to 1.5 mol.

Here, the valence of the base is the number of OH ⁻ that can be supplied by one molecule of the basic substance. For example, the valence of 1 mol of sodium hydroxide or 1 mol of potassium hydroxide is 1 mol. For example, the valence of 1 mol of calcium hydroxide is 2 mol.

  If the basic substance used is a monovalent basic substance (for example, sodium hydroxide or potassium hydroxide), the base valence is the same as the number of moles of the basic substance. In other words, the liquid contains the basic substance having the above-mentioned “specific molar value” (for example, 0.1 mol or more) with respect to 1 mol of the terminal carboxyl group of the polyamide resin contained therein.

  In addition, as a result of intensive studies by the present inventors, as the amount of the basic substance used for neutralizing the terminal carboxyl group of the polyamide resin is increased and the degree of neutralization is increased, the polyamide resin dispersion raw material liquid is increased. It has been found that there is a relationship that increases the viscosity of. Therefore, in the present invention, the viscosity of the polyamide resin-dispersed raw material liquid can be increased to 300 mpa · s or more by adjusting the amount of the basic substance.

  The polyamide resin dispersion raw material liquid has a viscosity of 300 mpa · s or more, preferably 300 mpa · s or more and 10,000 mpa · s or less, more preferably 500 mpa · s or more and 5000 mpa · s or less. By adjusting the viscosity to 300 mpa · s or more, the effect of the stirring process described later becomes remarkable, excellent in stability and adhesion, and excellent in adhesion between the fiber and the matrix resin when the fiber is treated. An aqueous dispersion can be obtained.

  Examples of the polymer dispersant used in the present invention include polyvinyl pyrrolidone, polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, polyacrylate, polyacrylate salt, sodium alginate, polyethylene glycol, polyalkylene polyamine, ethylene oxide. / Propylene oxide copolymer. The polymer dispersant can be used alone or in combination of two or more.

  Among these, the compatibility with the polyamide resin is excellent, the change with time of viscosity, which is a characteristic of the aqueous polyamide resin dispersion obtained by the present invention, is excellent in stability, and when used as a fiber treatment agent, the fiber Polyvinyl pyrrolidone, polyethylene glycol, ethylene oxide / propylene oxide copolymer, etc. are excellent from the viewpoint of obtaining a polyamide resin aqueous dispersion capable of obtaining a fiber composite material having excellent adhesion between the resin and the matrix resin. In particular, polyvinylpyrrolidone is preferably used in view of the excellent heat resistance.

  Polyvinyl pyrrolidone (PVP) may be a polymer obtained by polymerizing vinyl pyrrolidone, and may be a polymer containing polyvinyl pyrrolidone as a copolymer. These can use what is marketed. The mass average molecular weight of polyvinylpyrrolidone is not particularly limited, but is preferably 10,000 to 5,000,000, and in particular, 100,000 to 3,000,000 from the viewpoint that the aqueous polyamide resin dispersion obtained is excellent in stability. Is more preferable.

  The amount of the polymer dispersant used (the amount contained in the polyamide resin dispersion raw material liquid) is not particularly limited, but is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyamide resin. A mass part is more preferable, and 1-6 mass parts is still more preferable. When the amount of the polymer dispersant used is 0.01 parts by mass or more, it is preferable from the standpoint of stationary stability, for example, there is little change in the viscosity of the resulting aqueous polyamide resin dispersion. When the amount of the polymer dispersant used is 10 parts by mass or less, when the fiber is treated as a fiber treating agent, the adhesion between the fiber and the matrix resin is better, which is preferable.

  In particular, in one aspect of a preferred method for producing the above-mentioned polyamide resin dispersion raw material liquid, the polymer dispersant can be used as a base terminal carboxyl group in the polyamide resin without adding it in the initial adjustment stage of the mixed liquid. It can be added arbitrarily at any time until it is neutralized with an organic substance, self-emulsified and an emulsion is obtained, and the effects of the present invention can be obtained. However, from the standpoint that the standing stability and adhesiveness of the resulting polyamide resin aqueous dispersion are particularly good, it is added to the polyamide resin until the terminal carboxyl group of the polyamide resin is neutralized with a basic substance. It is preferable to keep it.

  As the aqueous medium used in the present invention, water or a medium containing water as a main component is preferable, and water is more preferable. As water, various kinds of water such as tap water, industrial water, ion exchange water, deionized water, and pure water can be used. Deionized water and pure water are particularly preferable. In addition, a pH adjuster, a viscosity adjuster, a fungicide, an antifoaming agent, and the like may be appropriately added to the water to be used, as long as the object of the present invention is not impaired.

  “Aqueous” in the aqueous polyamide resin dispersion of the present invention means containing an aqueous medium.

  The method for producing a polyamide resin aqueous dispersion of the present invention is characterized in that the polyamide resin dispersion raw material liquid is stirred at a specific tip peripheral speed and at a specific number of passes.

  A stirrer is used for stirring. Stirring is performed under the condition that the tip convergence of the stirrer is 10 m / s or more.

  There is no particular limitation on the stirrer for stirring the polyamide resin-dispersed raw material liquid so that the tip peripheral speed of the stirrer is 10 m / s or more. Can be used.

  Examples of the normal type agitator include, for example, a multiblade turbine blade, a flat turbine blade, a flat paddle blade, a pitched turbine blade, a pitched paddle blade, a propeller blade, an anchor blade and the like provided with a simple and inexpensive stirring blade. It is done. These can be used as an internal insertion type that is inserted from above into a container containing a processing solution and stirred.

  In addition, examples of the high-speed rotating stirrer include a high-speed rotating centrifugal radiation stirrer and a high-speed rotating shearing stirrer. As the high-speed rotating centrifugal radiation type stirrer, for example, one provided with a toothed disk type impeller in which circular saw blades are alternately bent up and down can be used. An insertion type TK homodisper or the like can be used. The high-speed rotary shear type stirrer has a shape in which the rotor blades are housed in the fixed blades, and atomizes the fluid using the powerful shearing action and impact force that occurs in the minute gaps between them. Internal insertion type and continuous circulation processing in which a processing blade is passed through a cylindrical vessel with fluid inlets and outlets inserted through a rotating blade and continuously circulated using a pump etc. There is a method type. Examples of the former include TK Robomix and TK homomixer manufactured by Primix Co., Ltd., and examples of the latter include TK pipeline homomixer and TK homomic line flow manufactured by Primix Co., Ltd. .

  In the present invention, it is possible to apply a strong shearing force and impact force to the polyamide resin-based dispersion raw material liquid, and the aqueous dispersion liquid of the present invention having excellent stability and adhesiveness is obtained and used as a fiber treating agent. At this time, from the viewpoint that a fiber composite material having excellent adhesion between the fibers and the matrix resin can be obtained, a high-speed rotating shear type stirrer can be suitably used.

  In the present invention, when the polyamide resin-dispersed raw material liquid is stirred with an internal insertion type stirrer, the tip peripheral speed of the blade of the stirrer is 10 m / s or more, and the number of passes P1 defined by the following formula (1) is 20 Perform under conditions of more than once. The tip peripheral speed of the blades of the stirrer is 10 m / s or more, preferably 10 to 40 m / s, more preferably 15 to 30 m / s. The pass number P1 is 20 times or more, preferably 30 times or more, more preferably 50 to 10000 times, still more preferably 100 to 3000 times, still more preferably 150 to 1000 times, and particularly preferably 200 to 500 times. .

In the present invention, the tip peripheral speed is a value calculated by the following equation.
Tip peripheral speed (m / s) = d × π × n / (100 × 60)
(Where n represents the number of revolutions of the stirring blade [rpm], and d represents the diameter of the stirring blade [cm])

In addition, the number of passes depends on the type of stirrer, and the calculation method varies.In the case of a normal stirrer, a high-speed rotating centrifugal radiation type stirrer, and an internal insertion type high-speed rotating shear type stirrer, Can be calculated.
Number of passes P1 = Q × Agitation time (min) / Total liquid amount (L)

Here, Q represents the discharge amount [L / min] and is represented by the following equation.
^{Q = Nq · n · d 3} /1000
(However, Nq represents the discharge coefficient, n represents the stirring blade rotation speed [rpm], and d represents the stirring blade diameter [cm].)

  Here, the discharge coefficient Nq varies depending on the shape of the stirring blades. Although the discharge coefficient can be calculated by actual measurement, a technical document of a stirrer manufacturer, for example, “Theory and practice of emulsification dispersion (practical): Special Machine Industries Co., Ltd. (currently Primex Corporation), Since the values calculated in “Published in 1997” and “Agitation technology: edited by Satake Chemical Machinery Co., Ltd., 1992” are described in advance, the values described can be used.

  In the present invention, when the polyamide resin-dispersed raw material liquid is agitated by a continuous circulation processing type agitator, the tip peripheral speed of the agitator blade is 10 m / s or more and the number of passes P2 defined by the following equation (2) is Perform under one or more conditions. The tip peripheral speed of the blade of the stirrer is 10 m / s or more, preferably 15 m / s or more, more preferably 20 m / s or more. The pass number P2 is one or more times, preferably 3 to 100 times, more preferably 3 to 20 times.

In the case of a high-speed rotating shear type stirrer of the continuous circulation processing method, the pass number P2 is a value calculated using the following equation.
Number of passes P2 = Flow rate (L / min) x Agitation time (min) / Total liquid volume (L)

 In the present invention, the reason why it is preferable to perform such a stirring operation is presumed as follows.

  That is, if the polyamide resin is considered from the molecular level, the polyamide resin has a highly polar amide bond and has an ionic functional group such as a carboxyl group or an amino group. In the following, they are also simply referred to as “particles” and exhibit complex electrolyte behavior. Therefore, the interaction that particles try to aggregate is strong. Polyamide resin aqueous dispersions tend to gradually increase in viscosity even when left standing, and it may be difficult to lower the viscosity unless the concentration of the polyamide resin in the aqueous dispersion is lowered with an aqueous medium or the like. However, this is presumed to be due to the aggregation action of the particles. Moreover, the aqueous dispersion liquid thickened by the aggregation action of particles is inferior in adhesiveness. For example, when used as a treating agent for fibers, it is presumed that the adhesiveness between the fibers and the matrix resin is deteriorated.

  This is because the functional groups such as carboxyl groups in the polyamide resin that form hydrogen bonds with the matrix resin on the particle surface are more unevenly distributed due to the aggregation of the particles, making it difficult to form hydrogen bonds with the matrix resin. However, the present inventors have found that by performing the stirring operation of the present invention, it is possible to obtain an aqueous dispersion excellent in stability in which particles are less likely to agglomerate and viscosity does not increase under standing. I found it.

  About the obtained aqueous dispersion, aggregation between particles was loosened and the dispersibility of the particles was improved, so that the fibers were easily impregnated uniformly. Furthermore, it has been found that the adhesiveness to the matrix resin is excellent and it is suitable as a fiber treating agent. This is presumed to be because the uneven distribution of ionic functional groups on the particle surface was eliminated by stirring, and the uniformization of ions on the particle surface advanced.

  The aqueous polyamide resin dispersion obtained by the production method of the present invention is a copolymer obtained by copolymerizing ethylene and an ethylenically unsaturated carboxylic acid (hereinafter also referred to as “copolymer of ethylene and ethylenically unsaturated carboxylic acid”). ), The stability and adhesiveness of the aqueous dispersion can be increased, and when used as a fiber treating agent, the adhesiveness between the treated fiber and the matrix resin can be further enhanced.

  Examples of the copolymer of ethylene and ethylenically unsaturated carboxylic acid include a copolymer obtained by copolymerizing ethylene and ethylenically unsaturated carboxylic acid (more specifically, a random copolymer of ethylene and ethylenically unsaturated carboxylic acid). Polymers, copolymers obtained by grafting unsaturated carboxylic acids onto polyethylene, and the like. Furthermore, the copolymer etc. which added and copolymerized components other than ethylene and ethylenically unsaturated carboxylic acid are mentioned.

  Examples of the ethylenically unsaturated carboxylic acid include unsaturated carboxylic acids and dicarboxylic acids having 6 or less carbon atoms. Specific examples of the unsaturated carboxylic acid having 6 or less carbon atoms include acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid. Specific examples of the dicarboxylic acid include maleic acid and fumaric acid. , Itaconic acid and the like are exemplified. Among these, acrylic acid or methacrylic acid is preferable. In addition, ethylenically unsaturated carboxylic acid can be used 1 type or in combination of 2 or more types.

  Moreover, in this invention, it can replace with the copolymer of ethylene and ethylenically unsaturated carboxylic acid, or can also use the salt of this copolymer together. For example, the copolymer ammonium salt or sodium salt obtained by self-emulsifying the copolymer using ammonia, sodium hydroxide, or the like can be used. More specifically, for example, ethylene-acrylic acid copolymer ammonium salt or sodium salt obtained by self-emulsifying ethylene-acrylic acid copolymer (copolymer of ethylene and acrylic acid) is preferably used. Can do. Commercial products can also be used as salts of ethylene and ethylenically unsaturated carboxylic acids. For example, the trade name “Zyxen A” manufactured by Sumitomo Seika Co., Ltd. can be used as the ethylene-acrylic acid copolymer ammonium salt.

  The timing of addition of these ethylene and ethylenically unsaturated carboxylic acid copolymers (or salts thereof) is not particularly limited, but may be added during the production of the polyamide resin dispersion raw material liquid before the stirring operation, or the stirring operation May be added after the aqueous polyamide resin dispersion is obtained.

  Further, the amount of the copolymer of ethylene and ethylenically unsaturated carboxylic acid (or a salt thereof) is not particularly limited, but is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polyamide resin. An amount part is more preferable.

  The aqueous polyamide resin dispersion obtained by the production method of the present invention may contain an antioxidant, if necessary, as long as the object of the present invention is not impaired. By including the antioxidant, thermal degradation of the polyamide resin can be suppressed, and when used as a fiber treatment agent, mechanical properties such as heat resistance of the obtained fiber or fiber composite material can be improved.

  The concentration of the polyamide resin in the aqueous polyamide resin dispersion obtained by the production method of the present invention is desirably 0.1 to 80% by mass, and more preferably 1 to 60% by mass. When the concentration of the polyamide resin is 80% by mass or less, it is more preferable in terms of stability of the aqueous dispersion. When the concentration of the polyamide resin is 0.1% by mass or more, it is more preferable in terms of adhesiveness.

  In the aqueous polyamide resin dispersion obtained by the production method of the present invention, the average particle diameter of the dispersed polyamide resin particles is usually 0.1 to 20 μm. When the average particle size is 0.1 μm or more, the viscosity of the dispersion is more suitable and easier to handle. When the average particle size is 20 μm or less, the polyamide resin particles are more difficult to settle. In addition, when used as a fiber treating agent, uniform impregnation into fibers is more preferable. Here, the value of the average particle diameter is a value obtained by a laser diffraction / scattering method. Note that a particle to be measured that shows the same diffraction / scattered light pattern as a sphere having a diameter of 1 μm is calculated as a particle diameter of 1 μ regardless of its shape.

  The aqueous polyamide resin dispersion obtained by the present invention can be suitably used as a fiber treating agent. The polyamide resin aqueous dispersion itself may be used as a fiber treating agent, or a component that can be usually contained in a fiber treating agent is further added to the polyamide resin aqueous dispersion and then used as a fiber treating agent. Also good. That is, this invention includes the processing agent for fibers containing the said polyamide resin aqueous dispersion.

  The fiber to be treated by the fiber treating agent is not particularly limited. Examples of organic fibers include natural fibers such as cotton, hemp, flax, jute, wool, and cashmere obtained from plants and animals, polyamide synthetic fibers such as 6-nylon and 66-nylon obtained by synthesizing organic chemicals, Synthetic fibers such as polyester synthetic fibers, polyacrylonitrile synthetic fibers, polyvinyl alcohol synthetic fibers, polyvinyl chloride synthetic fibers, polyvinylidene chloride synthetic fibers, polyethylene synthetic fibers, polypropylene synthetic fibers, and polyurethane synthetic fibers Examples thereof include semi-synthetic fibers such as acetate and triacetate, and regenerated fibers such as rayon and cupra. Examples of the inorganic fiber include various fibers such as carbon fiber, glass fiber, metal fiber, and rock fiber manufactured by carbonizing at high temperature using acrylic fiber or pitch as a raw material.

  Among them, from the viewpoint of excellent compatibility with the aqueous polyamide resin dispersion obtained by the present invention and easy impregnation of the fiber with the treatment agent, polyamide fibers are preferable as organic fibers, and carbon fibers are preferable as inorganic fibers. Can be used for

  The polyamide fiber used when the polyamide resin aqueous dispersion is used as a treating agent for polyamide fiber is not particularly limited. 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymer nylon, 6/610 copolymer nylon, 6/11 copolymer nylon, 6/12 copolymer nylon, 6 / 66/11 copolymer nylon, 6/66/12 copolymer nylon, 6/66/11/12 copolymer nylon, 6/66/610/11/12 copolymer nylon, and dimer acid polyamide resin, copolymerization thereof A fiber composed of a polyamide elastomer or the like which is a copolymer of nylon and polyester or polyalkylene ether glycol is preferably used.

  The carbon fiber used when the aqueous polyamide resin dispersion is used as a carbon fiber treating agent is not particularly limited. Specific examples of the carbon fiber include polyacrylonitrile-based carbon fiber, rayon-based carbon fiber, lignin-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, carbon nanotube, and the like, but the type is not particularly limited. Polyacrylonitrile-based carbon fibers are preferably used in that low cost can be realized and a molded product obtained from a carbon fiber bundle formed by bundling carbon fibers has good mechanical properties.

  Regarding the form, any of continuous long fibers, short fibers obtained by cutting continuous long fibers, milled yarn pulverized into a powder form, and the like may be used. These can be appropriately selected in the form of a sheet such as a woven fabric, a knitted fabric, or a non-woven fabric according to the application and required characteristics.

  The method for impregnating the fiber with the fiber treatment agent is not particularly limited. For example, the fiber is impregnated into a treatment tank containing a polyamide resin aqueous dispersion as the fiber treatment agent, and then the fiber is lifted. In addition to the method of dropping and spraying the fibers on the fibers, a knife coating method, a roller dipping method, a roller contact method, or the like can be applied. The amount of adhesion to the fiber can be adjusted by adjusting the polyamide resin concentration in the aqueous dispersion. Moreover, it can also adjust by wiping off the polyamide resin adhering to the fiber surface using an aperture controller or the like.

  After the fiber treating agent is adhered to the fibers, the water treated by the drying treatment is subsequently removed to obtain the fibers treated with the fiber treating agent obtained by the present invention.

  A method for the drying treatment at this time is not particularly limited, but a method using a heat medium such as hot air, a hot plate, a roller, an infrared heater or the like can be selected.

  The adhesion amount of the fiber treatment agent of the fiber to which the fiber treatment agent obtained from the present invention is adhered can be represented by the increase in the mass of the fiber after adhesion with respect to 100 parts by mass of the fiber before adhesion. The adhesion amount of the fiber treatment agent is desirably 0.1 to 20 parts by mass, and more preferably 1 to 15 parts by mass. If the amount of adhesion is less than 20 parts by mass, the flexibility of the fiber is not impaired and it can be used satisfactorily. If the adhesion amount is more than 0.1 parts by mass, the fiber-matrix resin has better adhesion when the fiber-matrix resin is blended to produce the fiber-composite material, and the strength of the fiber-composite material. The mechanical properties can be excellent.

  The fiber treated with the fiber treating agent of the present invention can be mixed with a matrix resin and used as a fiber reinforced resin composition. Here, the matrix resin is not particularly limited to either a thermosetting resin or a thermoplastic resin. In addition to being excellent in compatibility with the aqueous polyamide resin dispersion of the present invention, the mechanical properties of the obtained molded product are also included. In addition, it is possible to perform press molding or injection molding with high molding efficiency, and the thermoplastic resin is more preferable in consideration of the recycling aspect.

  As thermoplastic resins, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polyethylene, polypropylene, and polybutylene, styrene resins, polyoxymethylene, polyamide, polycarbonate, polymethylene methacrylate, polyvinyl chloride, polyphenylene sulfide, Polyphenylene ether, polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyketone, polyetherketone, polyetheretherketone, polyarylate, polyethernitrile, phenolphenoxy resin, fluororesin, and polystyrene-based, polyolefine , Polyurethane, saturated polyester, polyamide, polybutadiene, polyisoprene System, and thermoplastic elastomers and fluorine-containing resins, their copolymers, modified product, and a blend of two or more of these resins can be exemplified.

  When the polyamide resin aqueous dispersion obtained by the present invention is used as a fiber treating agent, it has excellent stability and adhesive properties such as little change in viscosity over time. A fiber composite material having excellent adhesiveness can be obtained.

  The fiber composite material obtained in this way has good adhesion between the fiber and the matrix resin. For example, the fiber composite material is thinned and has excellent mechanical properties such as strength and bending properties. It makes it possible to produce materials. Such a fiber composite material is extremely useful as a structural material for manufacturing automobiles, aircraft, sports-related products, medical equipment, and the like, such as nylon and polyester used for clothing materials, carpets, airbags, and the like. It can be used in a wide range of applications as a fiber coating agent.

  Next, examples and comparative examples in the present invention will be described, but the present invention is not limited to these.

Example 1
<Preparation of polyamide resin aqueous dispersion raw material liquid>
240 g of 6/66/12 copolymer nylon (melting point: 159 ° C., terminal carboxyl group: 180 mmol / kg, terminal amino group: 10 mmol / kg) in a pressure-resistant autoclave equipped with a turbine-type stirring blade having a diameter of 50 mm and having an internal volume of 1 liter , 141.2 g of deionized water, 14 g of 10% sodium hydroxide aqueous solution, and 4.8 g of polyvinylpyrrolidone (trade name “PVP K-90” of ISP Japan Co., Ltd .: mass average molecular weight 900,000 to 1500,000) Sealed. Next, the agitator was started, and the temperature inside the autoclave was raised to 180 ° C. while stirring at a rotation speed of 1000 rpm. The mixture was further stirred for 30 minutes while maintaining the internal temperature at 180 ° C., then cooled, and when the internal temperature reached 90 ° C., 400 g of deionized water was added. Furthermore, it cooled to room temperature and obtained the polyamide resin aqueous dispersion raw material liquid. The average particle diameter of the polyamide resin in this raw material liquid was measured using a laser diffraction particle size distribution measuring apparatus (Shimadzu Corporation, trade name “SALD-2000J”). Moreover, the said raw material liquid was moved to a 25 degreeC thermostat, and the viscosity in 25 degreeC and 60 rpm was measured using the B-type rotary viscometer.

<Agitation of polyamide resin aqueous dispersion raw material liquid>
After 400 g of the raw material liquid obtained as described above was put into a 1 liter beaker, an internal insertion type high-speed rotary shearing type stirrer (trade name “TK Robotics” manufactured by Primics Co., Ltd .: stirring blade diameter 2.7 cm, discharge coefficient 0.15), a stirring operation was performed at 9000 rpm for 5 minutes (tip peripheral speed 12.7 m / s, number of passes P1; 332 times) to obtain an aqueous polyamide resin dispersion of the present invention.

In each example, since the density of the polyamide used was approximately 1 g / cm ³ , the number of passes was calculated by converting the density of the aqueous dispersion raw material liquid to 1000 g / L.

Example 2
A polyamide resin aqueous dispersion of the present invention was obtained in the same manner as in Example 1 except that the amount of 10% aqueous sodium hydroxide used was changed to 13.6 g in Example 1.

Example 3
In Example 1, except that the amount of 10% aqueous sodium hydroxide used was 13.0 g, the same operation as in Example 1 was performed to obtain an aqueous polyamide resin dispersion of the present invention.

Example 4
A polyamide resin aqueous dispersion of the present invention was obtained in the same manner as in Example 1 except that the amount of 10% aqueous sodium hydroxide used was changed to 15.8 g in Example 1.

Example 5
In Example 1, except that the stirring operation was performed at 12000 rpm for 5 minutes (tip peripheral speed 17.0 m / s, number of passes P1; 443 times), the aqueous polyamide resin of the present invention was used. A dispersion was obtained.

Example 6
In Example 1, instead of the internal insertion type high-speed rotary shear type stirrer, a normal type stirrer equipped with a flat paddle (4 blades, stirring blade diameter 7.7 cm, discharge coefficient 0.5) as a stirring blade was used. The aqueous polyamide resin dispersion of the present invention was treated in the same manner as in Example 1 except that the stirring operation was performed at 2500 rpm for 2 minutes (tip peripheral speed 10.1 m / s, number of passes P1; 2853 times). Obtained.

Example 7
In Example 1, instead of the internal insertion type high-speed rotary shearing type stirrer, a continuous circulation processing type high-speed rotary shearing type stirrer (trade name “TK Pipeline Homomixer SL type” manufactured by Primix Co., Ltd.): stirring blade diameter 4 8 cm) at a flow rate of 0.2 L / min at 9000 rpm for 2.5 minutes (tip peripheral speed 22.6 m / s, number of passes P2; 1.25 times). In the same manner as in No. 1, an aqueous polyamide resin dispersion of the present invention was obtained.

Example 8
In Example 7, the same operation as in Example 7 was carried out except that the stirring operation was performed for 10 minutes (tip peripheral speed 22.6 m / s, number of passes P2; 5 times) at a flow rate of 0.2 L / min. An aqueous polyamide resin dispersion of the invention was obtained.

Example 9
In Example 1, except that the usage-amount of polyvinylpyrrolidone was 1.2g, it operated similarly to Example 1 and obtained the polyamide resin aqueous dispersion of this invention.

Example 10
A polyamide resin aqueous dispersion of the present invention was obtained in the same manner as in Example 1 except that the amount of polyvinylpyrrolidone used was 9.6 g in Example 1.

Example 11
In Example 1, when 400 g of deionized water was added, an aqueous dispersion of ethylene-acrylic acid copolymer ammonium salt (trade name “Zyxen A” manufactured by Sumitomo Seika Co., Ltd .; solid content concentration 25%, acrylic acid A copolymer resin aqueous dispersion of the present invention was obtained in the same manner as in Example 1 except that 48 g (copolymerization ratio 21.1%) was added.

Example 12
96 g of an aqueous dispersion of ethylene-acrylic acid copolymer ammonium salt (trade name “Zyxen A” manufactured by Sumitomo Seika Co., Ltd .; solid content concentration 25%, acrylic acid copolymerization ratio 21.1%) was added. Except for the addition, the same operation as in Example 11 was performed to obtain an aqueous polyamide resin dispersion of the present invention.

Example 13
In Example 1, instead of 4.8 g of polyvinylpyrrolidone, 4.8 g of polyethylene glycol (trade name “PEG20000” of Daiichi Kogyo Seiyaku Co., Ltd .: mass average molecular weight 200,000) was used. The same operation was performed to obtain an aqueous polyamide resin dispersion of the present invention.

Example 14
When 400 g of deionized water was added, an aqueous dispersion of ethylene-acrylic acid copolymer ammonium salt (trade name “Zyxen A” manufactured by Sumitomo Seika Co., Ltd .; solid content concentration 25%, copolymerization ratio of acrylic acid 21. 1%) Except for the addition of 48 g, the same operation as in Example 13 was carried out to obtain an aqueous polyamide resin dispersion of the present invention.

Example 15
In Example 1, in place of 4.8 g of polyvinylpyrrolidone, 9.6 g of polyethylene glycol (trade name “PEG20000” of Daiichi Kogyo Seiyaku Co., Ltd .: mass average molecular weight 200,000) was used, and 400 g of deionized water was added. And 48 g of an aqueous dispersion of ethylene-acrylic acid copolymer ammonium salt (trade name “Zyxen A” manufactured by Sumitomo Seika Co., Ltd .; solid content concentration 25%, copolymerization ratio of acrylic acid 21.1%) The aqueous polyamide resin dispersion of the present invention was obtained in the same manner as in Example 1, except that the above was added.

Example 16
Instead of 9.6 g of polyethylene glycol, 12.0 g of an ethylene oxide / propylene oxide copolymer (trade name “Pluronic F108” manufactured by Asahi Denka Co., Ltd .; mass average molecular weight 15,500, ethylene oxide content 80% by weight) was used. Except for the above, the same operation as in Example 15 was carried out to obtain an aqueous polyamide resin dispersion of the present invention.

Example 17
The amount of 6/66/12 copolymer nylon is 144 g, and 96 g of polyamide elastomer (trade name “UBESTA XPA9044X2” manufactured by Ube Industries, Ltd .; polyether block amide copolymer, melting point 150 ° C.) is used. Then, a polyamide resin aqueous dispersion of the present invention was obtained in the same manner as in Example 16 except that the amount of 10% sodium hydroxide aqueous solution was changed to 5.6 g.

Comparative Example 1
In Example 1, except having not performed stirring operation, it operated similarly to Example 1 and obtained the polyamide resin aqueous dispersion.

Comparative Example 2
A polyamide resin aqueous dispersion was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone was not used in Example 1.

Comparative Example 3
A polyamide resin aqueous dispersion was obtained in the same manner as in Example 1 except that the amount of 10% aqueous sodium hydroxide used was changed to 11.9 g in Example 1.

Comparative Example 4
In Example 1, using a high-speed rotary shear type stirrer, the stirring operation was performed at 6000 rpm for 5 minutes (tip peripheral speed 8.5 m / s, number of passes P1; 221 times), as in Example 1. Operation was performed to obtain an aqueous polyamide resin dispersion.

Comparative Example 5
Example 1 is the same as Example 1 except that the stirring operation was performed at 9000 rpm for 15 seconds (tip peripheral speed 12.7 m / s, number of passes P1; 16.6 times) using a high-speed rotating shear stirrer. The same operation was performed to obtain an aqueous polyamide resin dispersion.

Comparative Example 6
Except that the stirring operation was performed at 3500 rpm for 2.5 minutes (tip peripheral speed 8.8 m / s, number of passes P2; 1.25 times), an aqueous polyamide resin dispersion was obtained in the same manner as in Example 7. It was.

Comparative Example 7
Except that the stirring operation was performed at a flow rate of 0.2 L / min for 1 minute (tip peripheral speed 22.6 m / s, number of passes P2; 0.5 times), the same operation as in Example 7 was carried out to obtain an aqueous dispersion of polyamide resin. A liquid was obtained.

(Standing stability evaluation)
The polyamide resin aqueous dispersions obtained in Examples 1 to 17 and Comparative Examples 1 to 7 were moved to a thermostat set at 25 ° C. and allowed to stand for 40 days, and then the particle diameter and viscosity were measured. The standing stability of the dispersion was evaluated. The results are shown in Table 1. Here, the evaluation criteria for the stationary stability evaluation are as follows.
A: Viscosity value and particle size value hardly change. (Increase rate is less than 20%)
○: Although the viscosity value is slightly increased (increase rate is less than about 100%), the particle size value is hardly changed.
(Triangle | delta): Both a viscosity value and a particle size value are a little large. (Viscosity value increase rate 100% or more, particle size value increase rate 20% or more)
X: Viscosity value and particle size value are greatly increased. (Viscosity value increase rate of 200% or more, particle size value increase rate of 50% or more)

(Adhesion evaluation 1)
The aqueous dispersions of polyamide resins obtained in Examples 1 to 17 and Comparative Examples 1 to 7 have a solid content concentration (total concentration of polyamide resin, basic substance, polymer dispersant, and ethylene acrylic acid copolymer). Diluted with deionized water to 8% by weight. 1 L of this polyamide resin aqueous dispersion was placed in an impregnation tank.

  Next, a carbon fiber bundle wound on a bobbin (trade name “Pyrofil TR50SI5L” manufactured by Mitsubishi Rayon Co., Ltd .: 15000 filaments, filament diameter 7 μm, basis weight 1000 mg / m) was sent out from the bobbin, and then Examples 1 to After continuous roller immersion in an impregnation tank containing the polyamide resin aqueous dispersions obtained in 17 and Comparative Examples 1 to 5, hot air drying (190 ° C. for 5 minutes) was performed. Here, the diaphragm after immersion is adjusted, and the amount of each polyamide resin aqueous dispersion after hot air drying is 3 parts by mass with respect to the case where the mass of the carbon fiber bundle before adhesion is 100 parts by mass. Adjusted.

The obtained carbon fiber bundle was placed on a nylon 6 sheet (length: 25 cm width: 3.5 cm, thickness: 0.5 mm), and then a press machine (manufactured by Toyo Seiki Seisakusho Co., Ltd.) set at a heating temperature of 240 ° C. Using a product name “thermal inclination tester”), heat fusion (bonding area 0.6 cm ² ) was performed at 0.2 MPa for 30 seconds, and then cut to prepare a test piece. With reference to JIS K6850, the tensile shear strength of the carbon fiber bundle and the nylon 6 sheet was measured using an autograph (trade name “AGS-J” manufactured by Shimadzu Corporation) under the condition of a tensile speed of 3 mm / min. When the peel strength was 4.5 MPa or more, it was judged that the adhesiveness was excellent.

(Adhesion evaluation 2)
The aqueous dispersions of polyamide resins obtained in Examples 1 to 17 and Comparative Examples 1 to 7 have a solid content concentration (total concentration of polyamide resin, basic substance, polymer dispersant, and ethylene acrylic acid copolymer). Diluted with deionized water to 20% by weight. 1 L of this polyamide resin aqueous dispersion was placed in an impregnation tank.

Next, a nylon 66 woven fabric (plain weave, warp: 46 / inch, weft: 46 / inch, using nylon 66 combined yarn with a total fineness of 470 dtex) cut into 15 cm × 3.5 cm is placed in an impregnation tank and dipped. Then, hot air drying (190 ° C., 5 minutes) was performed (adhesion amount 5%). Next, after cutting the woven fabric, it was overlaid with a nylon 6 sheet (length: 25 cm width: 3.5 cm, thickness: 0.5 mm) and set at a heating temperature of 240 ° C. (Toyo Seiki Seisakusho Co., Ltd.) Using a product name “thermal inclination tester” manufactured by the same company, heat fusion (bonding area 2.5 cm ² ) was performed under the conditions of 0.2 MPa and 90 seconds, and then cut to prepare a test piece. With reference to JIS K6850, the tensile shear strength of nylon 66 woven fabric and nylon 6 sheet was measured under the condition of a tensile speed of 3 mm / min using an autograph (trade name “AGS-J” manufactured by Shimadzu Corporation). When the peel strength was 1.2 Mpa or more, it was judged that the adhesiveness was excellent.

  The above results are shown in Tables 1 and 2.

From Tables 1 and 2, the polyamide resin aqueous dispersion obtained by the present invention has excellent stability and adhesiveness, such as little change in viscosity over time, and when treated with fibers as a fiber treating agent, It was found that the adhesiveness with the matrix resin was excellent.
On the other hand, the polyamide resin aqueous dispersion that does not perform the stirring operation of the present invention of Comparative Examples 1 to 7 or does not use a polymer dispersant is inferior in stability, such as a large change in viscosity over time, It was found that the adhesion with the matrix resin was poor.

  The aqueous polyamide resin dispersion obtained from the present invention has excellent stability and adhesiveness, such as little change in viscosity over time, so it is practically easy to use and when used as a fiber treatment agent to treat fibers Since the adhesiveness between the fiber and the matrix resin is good, a composite material with good mechanical properties such as strength can be produced when the fiber composite material is produced.

Claims (5)

Including a polyamide resin, a basic substance, a polymer dispersant and an aqueous medium,
A polyamide resin dispersion raw material liquid having a viscosity at 25 ° C. and 60 rpm in a B-type rotary viscometer of 300 mpa · s or more,
With the internal insertion type agitator, the tip peripheral speed of the agitator blade is 10 m / s or more and the number of passes P1 defined by the following formula (1) is 20 times or more, or
A polyamide resin aqueous dispersion which is stirred by a continuous circulation processing type stirrer at a tip peripheral speed of the stirrer blade of 10 m / s or more and a pass number P2 defined by the following formula (2) of 1 or more. Manufacturing method.
Formula (1)
Number of passes P1 = Q x stirring time (min) / total liquid volume (L)
Here, Q indicates the discharge amount [L / min] and is represented by the following equation.
^{Q = Nq · n · d 3} /1000
Nq: discharge coefficient n: stirring blade rotation speed [rpm] d: stirring blade diameter [cm]
Formula (2)
Number of passes P2 = Flow rate (L / min) x Agitation time (min) / Total liquid volume (L)  The method for producing an aqueous polyamide resin dispersion according to claim 1, wherein the stirrer is a rotary shear stirrer. The polyamide resin dispersion raw material liquid is
A mixed liquid containing a polyamide resin, a basic substance, a polymer dispersant, and an aqueous medium is an emulsion obtained by stirring and emulsifying at a temperature higher than the softening temperature of the polyamide resin.
The manufacturing method of the polyamide resin aqueous dispersion of Claim 1 or 2.   The method for producing an aqueous polyamide resin dispersion according to any one of claims 1 to 3, wherein the polymer dispersant is at least one selected from the group consisting of polyvinylpyrrolidone, polyethylene glycol, and an ethylene oxide / propylene oxide copolymer. In the polyamide resin dispersion raw material liquid,
The manufacturing method of the polyamide resin aqueous dispersion in any one of Claims 1-4 in which 0.01-10 mass parts of polymer dispersing agents are contained with respect to 100 mass parts of polyamide resins.