JP2018070776A - Adhesive additive for plastisol and plastisol using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive additive capable of providing a plastisol excellent in low temperature curability and storage stability.SOLUTION: There is provided an adhesive additive for plastisol constituted by a main agent (M) containing a blocked urethane prepolymer (C) containing polyol (A), polyisocyanate (B) and a blocking agent (E) as constitutional monomers, and a curing agent (H). (A) contains THF/AO copolymer or polytetramethylene glycol (A1) containing a repeating unit of an oxytetramethylene group of 80 to 99.7 wt.% and AO copolymer other than PO/PO or polypropylene glycol (A2) containing the repeating unit of an oxypropylene group of 80 to 99.7 wt.% and the (B) is selected from a burette body (b1) of polymethylene diisocyanate (p), an isocyanurate body of (p) (b2) and an adduct body (b3) of polyalcohol and (p).SELECTED DRAWING: None

Description

  The present invention relates to an adhesion-imparting agent used for plastisols.

  Conventionally, various plastisols for coating are blended with an adhesion-imparting agent in order to improve adhesion to an object to be coated. The adhesion imparting agent for plastisol coated on steel plates for automobiles contains a base agent and a curing agent as a base material, and the main component is an isocyanate group-terminated urethane obtained by reacting a polyol with an organic polyisocyanate. A block product of a prepolymer (see, for example, Patent Document 1) is known. However, when the adhesion-imparting agent described in Patent Document 1 is used, the paintability (coating appearance), chipping resistance, and warm water resistance on the metal painted surface are excellent, but sufficient for both low temperature curability and storage stability. It was not satisfactory.

JP 59-78279 A

  An object of the present invention is to provide an adhesion-imparting agent capable of obtaining a plastisol excellent in low-temperature curability and storage stability.

  The inventor of the present invention has arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention includes a main agent (M) containing a blocked urethane prepolymer (C) having a polyol (A), a polyisocyanate (B) and a blocking agent (E) as constituent monomers, and a curing agent (H ), A tetrahydrofuran / 1,2-alkylene oxide copolymer or polytetramethylene in which the polyol (A) contains 80 to 99.7% by weight of repeating units of an oxytetramethylene group. It contains glycol (A1) and an alkylene oxide copolymer other than 1,2-propylene oxide / 1,2-propylene oxide or polypropylene glycol (A2) containing 80 to 99.7% by weight of repeating units of oxypropylene group. And polyisocyanate (B) is polymethylene diisocyanate At least one poly selected from the group consisting of a polymethylene diisocyanate isocyanurate (b2) and an adduct (b3) of polymethylene diisocyanate and a polyhydric alcohol to which no alkylene oxide is added. A plastisol adhesion-imparting agent containing isocyanate (B1); a plastisol comprising an acrylic polymer or vinyl chloride polymer, the adhesion-imparting agent, and a plasticizer; and a cured product of the plastisol on the surface of the steel sheet. It is an anti-chipping steel plate at least partially.

  By using the adhesion-imparting agent of the present invention, a good plastisol having both low-temperature curability and storage stability can be obtained.

The adhesiveness imparting agent for plastisol of the present invention has a main agent (M) and a curing agent (H) as constituent components. The main agent (M) is a main agent composed of a blocked urethane prepolymer (C) having a polyol (A), a polyisocyanate (B) and a blocking agent (E) as constituent monomers, and the polyol (A) Tetrahydrofuran / 1,2-alkylene oxide copolymer or polytetramethylene glycol (A1) containing 80 to 99.7% by weight of repeating units of oxytetramethylene group and 80 to 99.7% of repeating units of oxypropylene group % -Containing 1,2-propylene oxide / 1, alkylene oxide copolymer other than 1,2-propylene oxide or polypropylene glycol (A2), and polyisocyanate (B) is a polymethylene diisocyanate burette (b1), Isocyanurate of polymethylene diisocyanate A blocked urethane prepolymer containing at least one polyisocyanate (B1) selected from the group consisting of an adduct (b3) of a polyhydric alcohol to which no alkylene oxide is added and polymethylene diisocyanate (b3) It is the main agent (M1) consisting of (C1).
From the viewpoint of improving the low temperature curability, the polyol (A) preferably has a weight ratio of (A1) to (A2) of 95/5 to 10/90, more preferably 80/20 to 20/80.

As polyisocyanate (B), from the viewpoint of low-temperature curability, polymethylene (carbon number: 2 to 12) diisocyanate burette (b1), polymethylene (carbon number: 2 to 12) diisocyanate isocyanurate (b2) and Even when the coating film is thick by using at least one (B1) selected from the group consisting of an adduct (b3) of a polyhydric alcohol not added with alkylene oxide and a polymethylene (carbon number: 2 to 12) diisocyanate Excellent low-temperature curability not only on the coating surface but also inside the coating.
As the polyhydric alcohol to which no alkylene oxide is added, known polyhydric alcohols can be used, and trihydric or higher alcohols are preferred. Specific examples include trimethylolpropane, glycerin and pentaerythritol.

The blocked urethane prepolymer (C) refers to a product obtained by adding a blocking agent (E) to the terminal NCO group of the urethane prepolymer obtained by the reaction with the polyol (A) and the polyisocyanate (B).
The weight ratio of (B), (A) and (E) is 50 to 90/5 to 40/5 to 20 from the viewpoint of low temperature curability.

In addition to the above (B1), the polyisocyanate (B) may be used in combination with an aliphatic polyisocyanate from the viewpoint of the storage stability of the paint. Aliphatic polyisocyanates include aliphatic polyisocyanates having chain hydrocarbons and alicyclic polyisocyanates.
Specific examples of the aliphatic polyisocyanate having a chain hydrocarbon include aliphatic diisocyanates having 4 to 12 carbon atoms (such as 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate). Is mentioned.
Specific examples of the alicyclic polyisocyanate include alicyclic diisocyanates having 8 to 18 carbon atoms (such as isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate). It is done. If necessary, other organic polyisocyanates; for example, araliphatic polyisocyanates and organic isocyanate modified products (urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, isocyanurate groups, oxazolidone group-containing modified products, etc. ) Can be used in combination.

(B1) in the present invention may be used alone or in combination of two or more. From the viewpoint of low-temperature curability, 1,6-hexamethylene diisocyanate burette (b12), 1,6 It is preferable to use a hexamethylene diisocyanate isocyanurate (b21) and a polyhydric alcohol to which no alkylene oxide is added and an adduct (b31) of 1,6 hexamethylene diisocyanate alone, and more preferably 1 , 6-hexane diisocyanate nurate (b21) is used alone.

Polyol (A) is a tetrahydrofuran / 1,2-alkylene oxide copolymer or polytetramethylene glycol (A1) containing 80 to 99.7% by weight of repeating units of an oxytetramethylene group based on the weight of (A1). And an alkylene oxide copolymer other than 1,2-propylene oxide / 1,2-propylene oxide or polypropylene glycol containing 80 to 99.7% by weight of the repeating unit of oxypropylene group based on the weight of (A2) (A2 ). In (A1), if the repeating unit of the oxytetramethylene group is less than 80% by weight, the low-temperature curability deteriorates. In (A2), if the repeating unit of the oxypropylene group is less than 80% by weight, the low-temperature curability deteriorates.
(A1) preferably contains 90 to 99.7% by weight of repeating units of an oxytetramethylene group, more preferably 95 to 99.7% by weight of repeating units of an oxytetramethylene group. (A2) preferably contains 90 to 99.7% by weight of repeating units of oxypropylene groups, more preferably 95 to 99.7% by weight of repeating units of oxypropylene groups.
In both (A1) and (A2), the hydroxyl equivalent is preferably 250 to 3,000. The polyol (A) may contain a low molecular polyol (hydroxyl equivalent: less than 31 to 250) as necessary. Furthermore, in addition to (A1) and (A2), the polyol (A) may be used in combination with other polyether polyols, polyester polyols, polymer polyols, and the like. Moreover, polyhydric alcohol etc. are mentioned as a low molecular polyol.

Examples of (A1) include alkylene oxide (specifically, tetrahydrofuran and 3-methyl-tetrahydrofuran) adducts of a low molecular glycol (a dihydric alcohol of a low molecular polyol described later).
Examples of (A2) include alkylene oxide (specifically 1,2- or 1,3-propylene oxide: hereinafter abbreviated as PO) adducts of low molecular glycols.

Examples of the polyester polyol used in combination with (A1) and (A2) as necessary include condensed polyester polyols, polylactone polyols, castor oil-based polyols, and polycarbonate polyols.
The condensed polyester polyol includes a low molecular weight polyol and / or a polyether polyol having a hydroxyl group equivalent of 500 or less, a polycarboxylic acid (a dicarboxylic acid and, if necessary, a trivalent or higher polycarboxylic acid), and / or And polycondensates with the ester-forming derivatives.

  As the polycarboxylic acid, dicarboxylic acid, and dicarboxylic acid and a small proportion (for example, 10 equivalent% or less) of trivalent to tetravalent or higher polycarboxylic acid can be used. Examples thereof include aliphatic polycarboxylic acids having 2 to 12 carbon atoms [dicarboxylic acids (such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid and itaconic acid) and tricarboxylic acids. (Hexane tricarboxylic acid etc.), etc.], C8-15 aromatic polycarboxylic acid [dicarboxylic acid (terephthalic acid, isophthalic acid, phthalic acid etc.), tri- or tetracarboxylic acid (trimellitic acid, pyromellitic acid etc.) Etc.] and alicyclic polycarboxylic acids having 6 to 40 carbon atoms (eg, dimer acid). Examples of ester-forming derivatives include acid anhydrides, lower alkyl (1 to 4 carbon atoms) esters and acid halides (such as acid chlorides).

Of the polycarboxylic acids, a dicarboxylic acid is preferred from the viewpoint of the viscosity of the acrylic plastisol, an aliphatic dicarboxylic acid having 2 to 12 carbon atoms is more preferred, and adipic acid is particularly preferred.
The polylactone polyol is a lactone (having 4 to 15 carbon atoms, for example, ε-caprolactone, γ-butyrolactone, -Valerolactone) is subjected to ring-opening polymerization.
Castor oil-based polyols include castor oil (ricinoleic acid triglyceride) and transesterification products thereof. The transesterification product is obtained, for example, by transesterification between castor oil and the low molecular polyol and / or polyether polyol.

  As the polycarbonate polyol, ring-opening addition / polycondensation of alkylene carbonate using a low molecular polyol as an initiator described later, polycondensation (transesterification) of the low molecular polyol and diphenyl or dialkyl carbonate, or low molecular polyol or dihydric phenol described below. What is obtained by phosgenation of (bisphenol A etc.) is mentioned. Examples of the alkylene carbonate include those having an alkylene group having 2 to 6 carbon atoms, such as ethylene or propylene carbonate. Examples of the dialkyl carbonate include those having an alkyl group having 1 to 4 carbon atoms, such as dimethyl, diethyl or di- i-propyl carbonate is mentioned.

  The polymer polyol is a vinyl monomer [acrylic monomer such as (meth) acrylonitrile, alkyl (carbon number 1) in a polyol [for example, the above-described polymer polyol (polyether polyol, polyester polyol, etc.) and a mixture of these and a low molecular polyol described later]]. -20) (meth) acrylate (such as methyl methacrylate), aromatic hydrocarbon monomer (carbon number 8-20, such as styrene), aliphatic hydrocarbon monomer (carbon number 2-20, such as α-olefin and butadiene) and the like These two or more mixtures (such as a mixture of acrylonitrile and styrene)] are polymerized (polymer content is, for example, 5 to 70% by weight), for example, those described in JP-A No. 55-118948. Can be mentioned.

  Examples of the low molecular polyol having a hydroxyl group equivalent of 31 to 250 include those having the same composition as the polyhydric alcohol and the above-described polymer polyol having a hydroxyl equivalent of 250 to 3,000 and having a hydroxyl equivalent of 31 to less than 250.

Examples of polyhydric alcohols include dihydric alcohols, trihydric to octahydric or higher polyhydric alcohols, nitrogen-containing polyols (N0), and sulfo group-containing polyols.
Examples of the dihydric alcohol include those having 2 to 20 or more carbon atoms, such as aliphatic dihydric alcohols having 2 to 12 carbon atoms [(di) alkylene glycols such as ethylene glycol (hereinafter abbreviated as EG), diethylene glycol, propylene. Glycol, dipropylene glycol, 1,2-, 2,3-, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and 3-methylpentanediol, dodecanediol, etc.] C6-C10 alicyclic dihydric alcohol [1,4-cyclohexanediol and cyclohexanedimethanol etc.] and C8-C20 araliphatic dihydric alcohol [xylylene glycol and bis (hydroxyethyl) benzene etc. ].

  Examples of trihydric to octahydric or higher polyhydric alcohols include (cyclo) alkane polyols and intramolecular or intermolecular dehydrates thereof [glycerin, trimethylolpropane, pentaerythritol, sorbitol and dipentaerythritol, 1,2 , 6-hexanetriol, erythritol, cyclohexanetriol, mannitol, xylitol, sorbitan and diglycerin and other polyglycerin etc.] and sugars and derivatives thereof [eg sucrose, glucose, fructose, mannose, lactose and glucoside (methylglucoside etc.)] Is mentioned.

Examples of the nitrogen-containing polyol (N0) include tertiary amino group-containing polyols and quaternary ammonium group-containing polyols, and specifically nitrogen-containing diols such as aliphatic, alicyclic or aromatic having 1 to 12 carbon atoms. Group primary monoamines [methylamine, ethylamine, 1- or 2-propylamine, (iso) amylamine, hexylamine, 1,3-dimethylbutylamine, 3,3-dimethylbutylamine, 1-, 2- or 3-aminoheptane , Nonylamine, decylamine, undecylamine, dodecylamine, cyclopropylamine, cyclopentylamine, cyclohexylamine, aniline, benzylamine and the like] bishydroxyalkyl (carbon number 2 to 4) chloride [bis (2-hydroxyethyl) chloride and Bis (hydroxypropyl) compounds, such as A tertiary nitrogen atom-containing polyol described in Japanese Patent No. 4,271,217] and a quaternized product thereof [a quaternized product of a quaternizing agent or a dialkyl carbonate described in the above US patent specification]; Quaternary nitrogen atom-containing polyols described in US patent specifications; trivalent to octavalent or higher nitrogen-containing polyols such as trialkanol (2 to 4 carbon atoms) amine (triethanolamine, etc.) and 2 to 12 carbon atoms Polyhydroxyalkyl (2 to 4 carbon atoms) of aliphatic, cycloaliphatic, aromatic and heterocyclic polyamines (e.g., ethylenediamine, tolylenediamine and aminoethylpiperazine) [poly (2-hydroxyethyl) oxide, bis ( Hydroxypropyl) compounds: tetrakis (2-hydroxypropyl) ethylenediamine and pentakis (2-hydride) Kishipuropiru) diethylenetriamine] and similar quaternary compound with these above; and the like.

  Examples of the sulfo group-containing polyol include those obtained by introducing a sulfo group into the above dihydric alcohol and trihydric to octahydric or higher polyhydric alcohol, such as sulfoglycerin, sulfoerythritol, sulfodi (hydroxymethyl) benzene, sulfodi ( Hydroxyethyl) benzene, sulfodi (hydroxypropyl) benzene, sulfohydroxymethylhydroxyethylbenzene, and salts thereof [metal salts [alkali metal (such as lithium, sodium and potassium) salts, alkaline earth metal (such as calcium and magnesium) salts, Group IIB metal (such as zinc) salt], ammonium salt, amine (having 1 to 20 carbon atoms), quaternary ammonium salt and the like].

  Those having the same composition as the polymer polyol having a hydroxyl equivalent weight of 250 to 3,000 and having a hydroxyl equivalent weight of 31 to less than 250 include polyether polyols, polyester polyols and polyurethane polyols having a hydroxyl equivalent weight of 31 to less than 250. For example, low-polymerization alkylene oxide (hereinafter abbreviated as AO: details will be described later) ring-opening polymer and low-mol AO adduct of active hydrogen atom-containing polyfunctional compound [for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, Ethylene oxide 2-4 mol adduct of bis (hydroxyethoxy) benzene and bisphenol A], low-condensation condensation polyester polyol and low-mol lactone adduct of polyol [polycarboxylic acid and excess (1 mol per carboxyl group) Price Condensates (eg, dihydroxyethyl adipate) and EG caprolactone 1 mol adduct], and low-polymerization polyurethane polyol [reaction of isocyanate compound with excess (1 mol per isocyanate group) polyhydric alcohol Product (for example, reaction product of 1 mol of 2,4- or 2,6-tolylene diisocyanate and 2 mol of EG)].

The blocking agent (E) in the present invention is an oxime compound, a pyrazole compound, and a mixture thereof from the viewpoint of low-temperature curability, preferably a mixture of a pyrazole compound, an oxime compound, and a pyrazole compound, and more preferably a pyrazole. A compound. Specific examples of the oxime compound include oximes having 3 to 10 carbon atoms [for example, acetooxime, methyl ethyl ketoxime (MEK oxime) and methyl isobutyl ketoxime (MIBK oxime)]. As the oxime compound, methyl ethyl ketoxime and isobutyl ketoxime are preferable from the viewpoint of low-temperature curability. Examples of the pyrazole compound include pyrazole, 1,4 dimethylpyrazole, 3,5 dimethylpyrazole, and 3,5 diisopropylpyrazole. The pyrazole compound is preferably 1,4 dimethylpyrazole or 3,5 dimethylpyrazole from the viewpoint of low temperature curability. Moreover, you may use together blocking agents other than the above as needed. For example, lactams having 4 to 10 carbon atoms (for example, ε-caprolactam, δ-valerolactam and γ-butyrolactam), secondary amines having 2 to 20 carbon atoms [for example, aliphatic amines (such as dimethylamine and diisopropylamine), fats Cyclic amines (methylhexylamine, dicyclohexylamine, etc.) and aromatic amines (diphenylamine, etc.)], alkylphenols having 7 to 20 carbon atoms [for example, cresol, nonylphenol, xylenol and di-t-butylphenol], Patent Publication No. 2002-309217 Examples thereof include blocking agents described in JP-A No. 2008-239890 and a mixture of two or more thereof.

The blocked urethane prepolymer (C) in the present invention can be produced by reacting the polyol (A), the blocking agent (E) and the polyisocyanate (B).
The blocking agent (E) can be added and reacted at any stage of the urethane prepolymerization reaction. That is, the addition method includes (1) a method of adding the whole amount to (A) in advance, (2) a method of adding the whole amount in the initial stage of the urethane prepolymer formation reaction, and (3) a method in the initial stage or during the reaction of the urethane prepolymer reaction. And a method of adding the remainder at the end of the reaction, and (4) a method of adding the whole amount of the urethane prepolymer having an isocyanate group at the terminal after the production. Among these, the method (4) is preferable from the viewpoint of the reproducibility of the reaction.

  In the case of the above methods (1) to (3), the amount of (E) added is each isocyanate group of the raw material aromatic polyisocyanate (B) and aliphatic isocyanate (D) from the viewpoint of storage stability of plastisol. It is preferable to use approximately the same equivalent amount as that obtained by subtracting the active hydrogen-containing group equivalent number of the polyol (A) other than (E) from the total equivalent number of (E). In the case of the method (4), the isocyanate group of the urethane prepolymer From the viewpoint of storage stability, the amount is preferably 1 to 2 equivalents, more preferably 1.05 to 1.5 equivalents.

In the production of a urethane prepolymer having an isocyanate group obtained by reaction with (A) or (B) other than (E) in the method (4), an active hydrogen-containing group of (A) other than (E) And the equivalent ratio (active hydrogen-containing group / NCO group) in the reaction of (B) with the total isocyanate group (NCO group) is preferably from 1 / 1.3 in view of the viscosity of the main agent for imparting adhesion (M). 1/3, More preferably, it is 1 / 1.5 to 1 / 2.2.
The reaction temperature in the methods (1) to (4) is preferably 20 to 120 ° C., more preferably 60 to 110 ° C., from the viewpoint of suppressing side reactions. The reaction time is preferably 3 to 10 hours, more preferably 5 to 8 hours, from the viewpoint of suppressing side reactions.

  In order to accelerate the reaction, a known urethanization catalyst may be used. Urethane catalysts include metal catalysts (such as tin-based (trimethyltin laurate, trimethyltin hydroxide, dimethyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, stannous octoate and dibutyltin maleate), lead-based (olein). Lead acid, lead 2-ethylhexanoate, lead naphthenate, lead octenoate, etc., cobalt (such as cobalt naphthenate), bismuth {bismuth tris (such as 2-ethylhexanoate)} and mercury (phenylmercury propion) Acid salts, etc.], amine catalysts [triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, diazabicycloalkenes {1,8-diazabicyclo [5.4.0] -7-undecene} and the like; dialkylamino Alkylamines {dimethyl Minoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminoethylamine, dimethylaminooctylamine, dipropylaminopropylamine, etc.] or heterocyclic aminoalkylamines [2- (1-aziridinyl) ethylamine and 4- (1 -Piperidinyl) -2-hexylamine etc.] carbonate or organic acid salt (formate etc.), etc .; N-methylmorpholine, N-ethylmorpholine, triethylamine, diethylethanolamine, dimethylethanolamine etc.], and these 2 A mixture of seeds or more can be mentioned.

The amount of the urethanization catalyst used is preferably 1% or less, more preferably 0.001 to 0.1%, based on the weight of the urethane prepolymer obtained.
The isocyanate group content [NCO% (weight% in terms of solid content)] of the urethane prepolymer having an isocyanate group in the method (4) is preferably 1 to 20%, more preferably 2 to 2 from the viewpoint of plastisol adhesion. 15%. NCO% can be measured by a titration method or an infrared absorption spectrum method.
The number average molecular weight (hereinafter abbreviated as Mn) of the urethane prepolymer having an isocyanate group in the method (4) is preferably 500 to 8,000, more preferably 700 to 5,000. If Mn is 500 or more, the resin is soft and has a favorable effect on chipping resistance, and if it is 8,000 or less, fine particle formation (atomization) during coating of plastyl sol becomes better, and the appearance of the coating film (especially smoothness). Is better.

  Mn of the urethane prepolymer having an isocyanate group is measured by gel permeation chromatography using a tetrahydrofuran as a solvent and a polystyrene as a molecular weight standard substance after reacting the isocyanate group of the prepolymer with methanol.

The main agent (M) for the adhesion-imparting agent of the present invention may contain other components. The weight ratio of the other components is 0 to 900 parts by weight with respect to 100 parts by weight of the main agent.
Other components include a plasticizer (G) and a solvent (for example, aromatic hydrocarbon type, ester type, ether type and ketone type).

  The plasticizer (G) is contained for the purpose of viscosity adjustment. Specific examples include aromatic carboxylic acid esters [diethyl phthalate (DEP), dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DOP), dilauryl phthalate , Phthalates such as distearyl phthalate and diisononyl phthalate (DINP)], aliphatic carboxylic esters [methyl acetyl ricinoleate, di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl sebacate (DOS) , Adipic acid-propylene glycol polyester and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, etc.], phosphoric acid ester [triphenyl phosphate, tricresyl phosphate, etc.] and a mixture of two or more of these Cited That. Of these, aromatic carboxylic acid esters are preferred from the viewpoint of compatibility with (C), and DOP and DINP are more preferred.

  As a hardening | curing agent (H) which comprises the adhesiveness imparting agent of this invention, it is an active hydrogen group containing compound, and specifically, a polyol compound [The same thing as the compound as described in the said polyol (A) is mentioned. ], An amine compound, etc. are mentioned. Among these, the nitrogen-containing polyether polyol (N) which is an alkylene oxide adduct of the nitrogen-containing polyol (N0) is preferable from the viewpoint of low temperature curability.

From the viewpoint of curability, the weight ratio of the main agent (M) and the curing agent (H) in the adhesion-imparting agent of the present invention is preferably 20/80 to 98/2, more preferably 25/75 to 95/5. is there.
The plastisol of the present invention contains the adhesiveness-imparting agent of the present invention, a plasticizer (J), and an acrylic polymer or a vinyl chloride polymer.

  As an acrylic polymer, what is used for plastisol can be used, For example, what is described in Unexamined-Japanese-Patent No. 2007-39659 is mentioned. Among acrylic polymers, preferred from the viewpoint of chipping resistance are homopolymers of methyl (meth) acrylate and copolymers of methyl (meth) acrylate and other monomers, and more preferred are (meth). These are a homopolymer of methyl acrylate and a copolymer of methyl (meth) acrylate and butyl (meth) acrylate. An acrylic polymer may be used individually by 1 type, or may use 2 or more types together.

The Mn of the acrylic polymer is not particularly limited, but is preferably 100,000 to 5,000,000, more preferably 300,000 to 3,000,000 from the viewpoint of chipping resistance.
Mn of the acrylic polymer is measured by gel permeation chromatography using tetrahydrofuran as a solvent and polystyrene as a molecular weight standard substance.
The acrylic polymer is in the form of fine particles, and the volume average particle size of the fine particles is preferably 0.1 to 50 μm, more preferably 0.2 to 10 μm. The volume average particle diameter of the fine particles can be measured by, for example, a dynamic light scattering method using a laser diffraction / scattering particle size distribution measuring apparatus.

Examples of the vinyl chloride polymer include vinyl chloride homopolymers and copolymers with other vinyl monomers (such as vinyl acetate, maleic anhydride, maleic acid ester, and vinyl ether) that can be copolymerized with the vinyl chloride monomer.
The degree of polymerization of the vinyl chloride polymer is preferably 1000-1700. Commercially available vinyl chloride polymers include "Kanevinyl PSL-10", "Kanevinyl PSH-10" and "Kanevinyl PCH-12" [manufactured by Kaneka Corporation], "Zeon 121" and "Zeon 135J" [ Nippon Zeon Co., Ltd.], “Denka Vinyl PA-100” and “Denka Vinyl ME-180” [manufactured by Denki Kagaku Kogyo Co., Ltd.]. These may be used in combination of two or more.

The content of each component based on the total weight of the adhesiveness-imparting agent of the present invention, the plasticizer (J), the acrylic polymer and the vinyl chloride polymerization in the plastisol of the present invention is not particularly limited. It is as follows. Examples of the plasticizer (J) include the same plasticizer (G). The content of the adhesion-imparting agent is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, from the viewpoint of the adhesion of the plastisol to the metal coating surface. The content of the plasticizer is preferably 5 to 50% by weight, more preferably 10 to 45% by weight, from the viewpoint of chipping resistance. The content of the acrylic polymer or vinyl chloride polymer is preferably 10 to 80% by weight, more preferably 25 to 60% by weight, from the viewpoint of the viscosity of the plastisol.

  The plastisol can be blended with other additives (filler, foaming agent, colorant, stabilizer, diluent, etc.) as long as the effect of the present invention is not impaired, if necessary. The total amount of other additives is preferably 50% by weight or less, more preferably 1 to 40% by weight, based on the total weight of plastisol.

  As fillers, inorganic fillers (calcium carbonate, talc, clay, diatomaceous earth, silicic acid, silicate, kaolin, asbestos, mica, glass fiber, glass balloon, carbon fiber, metal fiber, ceramic whisker and titanium whisker) And organic fillers [cellulose powder, powder rubber, organic cross-linked fine particles (epoxy, urethane, etc.), urea, etc.]. The amount of the filler used is preferably 5% by weight or less, more preferably 0.1 to 2% by weight from the viewpoint of the viscosity of the plastisol, based on the total amount of the plastisol.

  Examples of the colorant include inorganic pigments, organic pigments, and dyes. Examples of inorganic pigments include white pigments, cobalt compounds, iron compounds (such as iron oxide and bitumen), chromium compounds, and sulfides. Examples of organic pigments include azo pigments and polycyclic pigments. As dyes, azo compounds, anthraquinone compounds, indigoid compounds, sulfur compounds, triphenylmethane compounds, pyrazolone compounds, stilbene compounds, diphenylmethane compounds, xanthene compounds, alizarin compounds, acridine compounds, Examples thereof include quinoneimine compounds, thiazole compounds, methine compounds, nitro compounds, nitroso compounds, and aniline compounds. The amount of the colorant used is preferably 5% by weight or less, more preferably 0.1 to 2% by weight, based on the total weight of the plastisol.

  Stabilizers include metal soaps (such as calcium stearyl and aluminum stearyl), inorganic acid salts (such as dibasic phosphites and dibasic sulfates), and organometallic compounds (such as dibutyltin dilaurate and dibutyltin maleate). E.g.). The amount of the stabilizer used is preferably 10% by weight or less, more preferably 0.2 to 5% by weight, based on the total weight of the plastisol.

  By applying the plastisol of the present invention to various metal (especially steel) surfaces and heat-treating them, it is possible to obtain a cured product having excellent coating appearance, chipping resistance, hot water resistance and adhesion to the metal coating surface. it can. The plastisol of the present invention can be applied to various undercoating surfaces, but can be advantageously applied particularly to a cationic electrodeposition coating surface from the viewpoint of plastisol adhesion.

The coating amount of plastisol is preferably 100 to 3,000 g / m ² from the viewpoint of chipping resistance, and the coating film thickness is preferably 0.1 to 3 mm from the viewpoint of chipping resistance. Examples of the application method include brush coating, spatula coating, roller coating, and airless spray coating. Airless spray coating is preferable from the viewpoint that coating efficiency and high-viscosity coating can be applied. In addition, although heat treatment is performed after coating, the heat treatment temperature is preferably 100 to 180 ° C., more preferably 110 to 160 ° C. from the viewpoint of plastisol adhesion and curability, and the heat treatment time is preferably 10 to 160 ° C. from the same viewpoint. 50 minutes, more preferably 15 to 40 minutes.
The anti-chipping steel plate in which the plastisol of the present invention is applied to at least a part of the surface of the steel plate and the plastisol is cured by heat treatment is excellent in all of the coating appearance, chipping resistance, hot water resistance and adhesion to the metal coating surface. Therefore, it can be used mainly as a steel plate in a portion where chipping is likely to occur, such as a lower surface of a vehicle body, a side sill, and a tire house, and rusting and corrosion due to chipping can be prevented.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following description, “parts” indicates parts by weight.
<Examples 1-6 and Comparative Examples 1-4>
A reaction vessel equipped with a stirrer and a thermometer was charged with the polyisocyanate compound (B), polyol (A) and plasticizer in the number of parts shown in Table 1, and the blocking agent (E) was added at 50 ° C. in a dry nitrogen atmosphere. Then, the terminal blocking reaction was carried out at the same temperature for 2 hours to obtain the main component of the adhesion imparting agent for plastisol of the present invention.
Furthermore, in Table 1, the adhesion imparting agents for plastisol (L-1) to (L-6) of the present invention and the adhesion imparting agents for plastisol (L′-1) to (L′-4) for comparison were obtained. .
In Table 1, all numbers other than the ratio indicate the number of copies prepared.

* 1 PTMG-3000: Polytetramethylenediol, manufactured by Mitsubishi Chemical Corporation, hydroxyl value = 37.4
* 2 Sannics PP-3000: Polyoxypropylene diol; manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value = 37.4
* 3 Sanix NP-400: Nitrogen-containing polyol; manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value = 700
* 4 Sanix GP-250: Polyoxypropylene triol; manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value = 670
* 5 TPA-100: Nurate of 1,6 hexane diisocyanate: Asahi Kasei * 6 24A-100: Bullet of 1,6 hexane diisocyanate: Asahi Kasei * 7 P301-75: 1,6 hexane diisocyanate 3 of trimethylolpropane Mole adduct (adduct) in 25% ethyl acetate solution: Asahi Kasei

<Examples 7 to 12 and Comparative Examples 5 to 8>
“Zeon F-320” [manufactured by Nippon Zeon Co., Ltd., methyl methacrylate polymer (Mn 3 million, volume average particle size) with respect to 107 parts of the adhesion imparting agent obtained in Examples 1 to 6 and Comparative Examples 1 to 4 1 μm diameter powder)] 169 parts, “Shiraka Hana CC-R” [manufactured by Shiraishi Kogyo Co., Ltd., surface treated ultrafine calcium carbonate (volume average particle size 0.08 μm)] 188 parts and diisononyl phthalate 189 parts To prepare plastisols (P-1) to (P-6) of the present invention and plastisols for comparison (P′-1) to (P′-4). Table 2 shows the results of measuring or evaluating the initial viscosity, viscosity after storage, storage stability, low temperature curability, adhesion, water resistance and chipping resistance by the method.

[Test method for performance evaluation of plastisol]
(1) Initial viscosity Viscosity at 25 ° C. immediately after plastisol production is measured using a BH viscometer [manufactured by Tokyo Keiki Co., Ltd.].
(2) Viscosity after storage Immediately after producing plastisol, 90 g of plastisol is placed in a glass sealed cylindrical container with an inner diameter of about 4 cm and a height of about 8 cm, and the viscosity after storage at 35 ° C. for 10 days is the same as in (1) above. To measure.
(3) Storage stability The rate of increase in viscosity (%) after storage with respect to the initial viscosity at the time of plastisol preparation is calculated from the following formula. The smaller the value, the better the storage stability.

(4) Low-temperature curing epoxy resin-based cationic electrodeposition coating [trade name: Konak / No. 3500, manufactured by Nippon Oil & Fats Co., Ltd.], a frame is attached to the coated surface of the coated steel sheet (hereinafter abbreviated as electrodeposition coated steel sheet) so that the content is 50 × 20 × 1 mm, and plastisol The film was coated with a spatula so that the film thickness was 1 mm, and after heat treatment at 110 ° C. for 20 minutes, the degree of cure of the coating film was judged by touch with the following criteria.
◎: No tack and good curability ○: Slightly tacky but hard enough for practical use Δ: There is tack and insufficient curability x: No cure at all

(5) the plastisol to the end of the coated surface of the electrodeposition coating steel adhesion vertical 100 mm × horizontal 25 mm × thickness 1mm (area of about 2 × 2 cm ²⁾ was spatula coating, so that the film thickness after compression becomes 1mm Then, the end of another electrodeposited steel sheet was crimped. In this state, after baking heat treatment at 110 ° C. for 20 minutes, the ends of the two electrodeposition coated steel sheets were pulled at a tensile speed of 50 mm / min. Evaluation was based on the criteria.
○: Cohesive failure △: Cohesive failure and interface peeling coexist ×: Interface peeling

(6) Warm water resistance As in (5) above, a test piece was prepared, baked at 110 ° C. for 20 minutes, and then immersed in warm water at 40 ° C. for 3 days. Was evaluated according to the same criteria as in (5).
(7) Chipping resistance A test piece obtained by applying plastisol to a coated surface of an electrodeposited steel sheet having a length of 100 mm, a width of 100 mm, and a thickness of 0.8 mm so that the film thickness is 400 μm, and baked at 110 ° C. for 20 minutes. Mounted on a nut dropping device, on a test piece having an angle of 45 ° with respect to the dropping direction of the nut through a 3 mm-M-4 shaped brass hexagon nut specified in JIS B 1181 through a tube with a diameter of 20 mm from a height of 2 m The nut was repeatedly dropped until the scratches on the coating film reached the metal surface, and a numerical value obtained by multiplying the weight of the nut (unit: kg) by the number of drops was calculated as a measure of chipping resistance. The larger this value, the better the chipping resistance.

The plastisol using the adhesiveness-imparting agent of the present invention not only has excellent low-temperature curability, but also has excellent coating appearance, chipping resistance, hot water resistance, storage stability, and adhesion to metal coating surfaces. It is particularly useful for the production of automotive skins and architectural soundproof sheets.

Claims (9)

  Consists of a main component (M) containing a blocked urethane prepolymer (C) comprising a polyol (A), a polyisocyanate (B) and a blocking agent (E) as constituent monomers, and a curing agent (H). In a plastisol adhesiveness-imparting agent, the polyol (A) is a tetrahydrofuran / 1,2-alkylene oxide copolymer or polytetramethylene glycol (A1) containing 80 to 99.7% by weight of repeating units of an oxytetramethylene group, and Containing an alkylene oxide copolymer or polypropylene glycol (A2) other than 1,2-propylene oxide / 1,2-propylene oxide containing 80 to 99.7% by weight of repeating units of oxypropylene group, and polyisocyanate ( B) is a bullet body of polymethylene diisocyanate (B1), at least one polyisocyanate (B1) selected from the group consisting of an isocyanurate of polymethylene diisocyanate (b2) and an adduct (b3) of polymethylene diisocyanate and a polyhydric alcohol to which no alkylene oxide is added. ) Plastisol adhesion promoter.   Polyisocyanate (B1) is 1,6 hexamethylene diisocyanate burette (b11), 1,6 hexamethylene diisocyanate isocyanurate (b21), polyhydric alcohol to which no alkylene oxide is added, and 1,6 hexamethylene diisocyanate The adhesiveness-imparting agent for plastisol according to claim 1, which is at least one polyisocyanate (B11) selected from the group consisting of adduct bodies (b31).   The weight ratio of tetrahydrofuran / 1,2-alkylene oxide copolymer or polytetramethylene glycol (A1) to alkylene oxide copolymer other than 1,2-propylene oxide / 1,2-propylene oxide or polypropylene glycol (A2) is The adhesiveness-imparting agent for plastisol according to claim 1 or 2, which is 95/5 to 10/90.   Tetrahydrofuran / 1,2-alkylene oxide copolymer or polytetramethylene glycol (A1) and alkylene oxide copolymer other than 1,2-propylene oxide / 1,2-propylene oxide or polypropylene glycol (A2) The adhesiveness-imparting agent for plastisol according to any one of claims 1 to 3, wherein the hydroxyl group equivalent is 250 to 3,000.   The adhesive imparting agent for plastisol according to any one of claims 1 to 4, wherein the blocking agent (E) of the blocked urethane prepolymer (C) is an oxime compound and / or a pyrazole compound.   The adhesive agent for plastisol according to any one of claims 1 to 5, wherein the curing agent (H) is an active hydrogen compound (N).   The adhesiveness-imparting agent for plastisol according to claim 6, wherein the active hydrogen compound (N) is a nitrogen-containing polyether polyol.   A plastisol comprising an acrylic polymer and / or a vinyl chloride polymer, the adhesion imparting agent for plastisol according to any one of claims 1 to 7, and a plasticizer (J).   An anti-chipping steel plate having the cured product of plastisol according to claim 8 on at least a part of the steel plate surface.