JP5173980B2 - Polyurethane-vinyl polymer composite resin aqueous dispersion - Google Patents

Description

  The present invention relates to a polyurethane-vinyl polymer composite resin aqueous dispersion and a method for producing the same.

  When applying a paint on the surface of an aluminum substrate such as an aluminum foil, an undercoat agent may be applied to the surface of the substrate in advance in order to improve the adhesion between the substrate and the coating film. However, when the base material is an aluminum foil or the like, the base material is often wound, and in this case, it is necessary that blocking does not occur.

  In recent years, from the viewpoint of the environment and the like, conversion from a solvent system to an aqueous system has been performed in the field of paints, and the conversion from a solvent system to an aqueous system is also required for the undercoat agent.

  On the other hand, Patent Document 1 discloses an undercoat agent composed of nitrified cotton and a polyol-ether urethane resin for the purpose of improving adhesion and preventing blocking. Moreover, as a water-based urethane resin composition, a composition using a polycarbonate diol-based polyurethane is described in Patent Document 2, and a composition using a carboxyl group-containing polyurethane is described in Patent Document 3.

JP 2001-11361 A JP 10-1110021 A JP 11-14149 A

  However, the undercoat agent composed of the above-mentioned nitrified cotton and polyol-ether type urethane resin is a solvent type and may have a problem on the environment. Moreover, about the water-based urethane resin composition using said polycarbonate diol-type polyurethane, and the water-based urethane resin composition using a carboxyl group-containing polyurethane, description about the adhesiveness and blocking resistance of a base material and a coating film There is no suggestion.

  Then, this invention aims at providing the aqueous dispersion which comprises the adhesiveness of a base material and a coating film, and anti-blocking property, and comprises the aqueous undercoat agent.

（式中、ｎは、正の整数を示す。また、Ｒは、炭素原子数２〜１２のアルキレン基を示す。） In the polyurethane-vinyl polymer composite resin aqueous dispersion obtained by dispersing polyurethane (A) and vinyl polymer (B) in an aqueous medium, the diol component constituting the component (A) A polycarbonate diol having a structural formula represented by the following formula (1) and having a number average molecular weight of 500 to 5,000, and having a hexamethylene unit as a linking group R in the following formula (1) among the polycarbonate diols However, the glass transition temperature (Tg) of the component (B) is 20 ° C. or more and 80 ° C. or less, and (B) per 100 parts by weight of the component (A). The above problems have been solved by using an aqueous dispersion of polyurethane-vinyl polymer composite resin having a component content of 20 parts by weight or more and 400 parts by weight or less. .

(In the formula, n represents a positive integer. R represents an alkylene group having 2 to 12 carbon atoms.)

Since this invention uses a composite resin aqueous dispersion having a polyurethane using a specific amount of a specific diol component, when used as an undercoat agent, the adhesion between the substrate and the coating film can be improved. , Blocking resistance can be improved.
Furthermore, since it is an aqueous dispersion, the environmental load can be reduced.

  The aqueous polyurethane-vinyl polymer composite resin dispersion according to the present invention is an aqueous polyurethane (hereinafter referred to as “component (A)”) and vinyl polymer (hereinafter referred to as “component (B)”). A liquid dispersed in a medium.

  The polyurethane constituting the component (A) is a polymer of a diol component and a polyisocyanate component. Examples of the polyisocyanate component include various aliphatic, alicyclic and aromatic organic diisocyanates. Specific examples of the diisocyanate compound include dicyclohexylmethane diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-tolylene diisocyanate, Examples include 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, and the like.

  Examples of the diol component include polycarbonate diol, carboxyl group-containing polyol, and other diols. Among these, it is necessary to use polycarbonate diol, and it is more preferable to use a carboxyl group-containing polyol in combination.

  The polycarbonate diol is a diol having a carbonate group, and includes a structural formula represented by the following formula (1).

  In the above formula (1), n represents a positive integer, preferably a positive integer of 2 to 40, and R represents an alkylene group having 2 to 12 carbon atoms. Of these R, hexamethylene units having 6 carbon atoms are particularly preferred. The proportion of the polycarbonate diol represented by the above formula (1) using a hexamethylene unit having 6 carbon atoms as R is required to have 40 mol% or more of the diol component used, and 45 mol% or more. It is preferable to have. If it is less than 40 mol%, the blocking resistance tends to deteriorate. In addition, the upper limit of the usage rate of this polycarbonate diol is 100 mol%.

  The upper limit of the number average molecular weight of the polycarbonate diol is 5000, and 3000 is preferable. When it is larger than 5000, the viscosity of the polyurethane prepolymer increases, and the aqueous dispersion obtained by emulsification tends to be unstable. On the other hand, the lower limit of the number average molecular weight is 500, preferably 1000. If it is smaller than 500, the resulting coating film becomes hard, so that cracks tend to occur, and the desired performance tends to be difficult to obtain.

  The carboxyl group-containing polyol is a polyol having a carboxyl group, and examples thereof include dimethylol alkanoic acids such as dimethylolpropionic acid and dimethylolbutanoic acid.

  Examples of the other diols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl-1,5-pentane. Diol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, trimethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane dimethanol, methylpentanediol adipate, polyester diol, polyether diol Etc.

  The vinyl polymer constituting the component (B) refers to a monomer having a vinyl group, that is, a polymer of a radical polymerizable monomer. In particular, it is more preferable to use a radically polymerizable monomer that does not contain active hydrogen, since it is difficult to consume an isocyanate that is not intended.

  The radical polymerizable monomer may be a monofunctional unsaturated monomer having only one vinyl group as a functional group, or a polyfunctional unsaturated monomer having two or more vinyl groups as a functional group. Good. Further, a mixture of a polyfunctional unsaturated monomer and a monofunctional unsaturated monomer may be used.

  Examples of the monofunctional unsaturated monomer include (meth) acrylic monomers, vinyl halide compounds, and aromatic vinyl compounds. In this specification, “(meth) acryl” means “acryl or methacryl”.

  The said (meth) acrylic-type monomer means (meth) acrylic acid or its ester compound, (meth) acrylic-acid alkylester, (meth) acrylic-type monomer, (meth) acrylic-acid alkoxyalkyl Ester etc. are mentioned, In the case of superposition | polymerization, the 1 type may be used or those 2 or more types of mixtures may be used.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth ) Cyclohexyl acrylate, benzyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, and the like.

  Examples of the alkoxyalkyl ester of (meth) acrylic acid include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, and the like.

  Examples of the vinyl halide compound include vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, and m-methylstyrene. , P-methylstyrene and the like.

  Examples of the polyfunctional unsaturated monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof.

Further, in addition to the above, N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, and compounds having three or more vinyl groups can be mentioned.
In addition, the monomer which has said vinyl group may be used independently, and 2 or more types may be mixed and used for it.

  Although the said (B) component is obtained by superposing | polymerizing the said radically polymerizable monomer, the upper limit of the glass transition temperature (Tg) of this (B) component is 80 degreeC, and 70 degreeC is preferable. If the temperature is higher than 80 ° C., the resulting coating film becomes hard, so that cracks are likely to occur, and it may be difficult to obtain desired performance. On the other hand, the lower limit of the glass transition temperature (Tg) is 20 ° C, preferably 30 ° C. When it is lower than 20 ° C., the adhesion tends to deteriorate.

Next, the manufacturing method of the polyurethane-vinyl polymer composite resin aqueous dispersion according to the present invention will be specifically described.
First, in the presence of a radical polymerizable monomer, a diol component containing the above polycarbonate diol and a carboxyl group-containing polyol is reacted with a polyisocyanate to produce a carboxyl group-containing polyurethane (a) step. Do.

  In the step (a), the urethane reaction is carried out in the presence of a radical polymerizable monomer, so that the viscosity during the reaction can be kept low and the reaction can be promoted uniformly.

As the radical polymerizable monomer, a monomer containing no active hydrogen is preferable.
Moreover, it is preferable to use a polyol containing a polycarbonate diol as the polyol, and to further use a polyol having a carboxyl group.

  The upper limit of the amount of the polycarbonate diol used is preferably 90% by weight, and preferably 85% by weight of the entire diol component. When the amount is more than 90% by weight, the amount of hydrophilic groups decreases, and the dispersion stability during water dispersion tends to deteriorate. On the other hand, the lower limit of the amount of the polycarbonate diol used is preferably 40% by weight, preferably 50% by weight, based on the entire diol component. When it is less than 40% by weight, the blocking resistance tends to deteriorate.

  In addition, the usage-amount with respect to the whole said diol component of polycarbonate diol shown by above-described Formula (1) needs to satisfy | fill said range.

  The upper limit of the amount of the carboxyl group-containing polyol used is preferably 30% by weight, preferably 20% by weight, based on the entire diol component. When it is more than 30% by weight, the water resistance of the resulting coating film tends to deteriorate. On the other hand, the lower limit of the amount of the carboxyl group-containing polyol used is preferably 5% by weight of the entire diol component, and preferably 10% by weight. When the amount is less than 5% by weight, the number of hydrophilic groups becomes relatively small, and the dispersion stability during water dispersion tends to be lowered.

  The mixing ratio of the diol component to the polyisocyanate is preferably a diol component / polyisocyanate = 1 / 1.1 to 1 / 2.5, preferably 1 / 1.2 to 1/2 in terms of weight ratio. When there is more diol component than 1 / 1.1, the viscosity at the time of reaction will rise and the dispersion state to water may deteriorate. On the other hand, if it is less than 1 / 2.5, unreacted isocyanate becomes excessive, and it may agglomerate when dispersed in water or generate coarse particles.

  The mixing ratio of the radical polymer monomer and the total amount of the diol component is the amount of the polyurethane as the component (A) and the vinyl polymer as the component (B) in the aqueous polyurethane-vinyl polymer composite resin dispersion obtained. The ratio is preferably such that the content of the component (B) is 20 to 400 parts by weight and preferably 25 to 300 parts by weight per 100 parts by weight of the component (A). When the amount is more than 400 parts by weight, the hydrophilicity necessary for water dispersion may be insufficient and the dispersion state may be deteriorated. On the other hand, when the amount is less than 20 parts by weight, the viscosity of the urethane polymer is increased, and it may be difficult to progress the reaction uniformly.

  Next, the step (b) of neutralizing the carboxyl group contained in the polyurethane obtained by the above polymerization with a basic compound is performed. Thereby, the obtained aqueous dispersion is further stabilized.

  The basic compound is not particularly limited as long as it can neutralize the carboxyl group, and includes alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, tertiary amines such as trimethylamine and triethylamine, and the like. can give.

  Next, step (c) is performed in which water is added to the obtained neutralized solution to disperse the polyurethane and the radical polymerizable monomer in water to obtain an aqueous dispersion. Subsequently, by performing the step (d) of polymerizing the radical polymerizable monomer to obtain a vinyl polymer, an aqueous polyurethane-vinyl polymer composite resin dispersion is produced.

  The amount of water used for obtaining the aqueous dispersion is not particularly limited, but is preferably 0.5 to 9 times by weight, more preferably 1 to 4 times by weight with respect to the neutralized solution. When the amount is more than 9 times by weight, the content ratio of the resin tends to decrease and it becomes difficult to obtain a thick coating film. On the other hand, when the amount is less than 0.5 times by weight, the viscosity at the time of water dispersion increases, and the handleability may deteriorate.

  In the step (c), an emulsifier is used as necessary. Examples of the emulsifier include ionic surfactants such as anionic, cationic and amphoteric, nonionic surfactants, and the like.

  In the step (d), the emulsion polymerization is performed by adding a polymerization initiator. As this polymerization initiator, a polymerization initiator used in usual emulsion polymerization can be used. Examples of the polymerization initiator include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvalero). Nitrile) and other azo compounds, hydrogen peroxide, hydroperoxides such as t-butyl hydroperoxide, radical polymerization initiators such as peroxides such as benzoyl peroxide and lauroyl peroxide, and these are independent. Or 2 or more types can be mixed and used. These radical polymerization initiators can be used as a redox polymerization initiator in combination with a reducing agent such as sodium sulfite, sodium hydrogen sulfite, sodium thiosulfate, tartaric acid, L-ascorbic acid.

  The polymerization temperature of the emulsion polymerization is preferably about 50 to 100 ° C., and the reaction time is usually preferably about 2 to 16 hours.

  The aqueous polyurethane-vinyl polymer composite resin dispersion thus obtained has excellent blocking resistance and excellent adhesion between the coating film and a substrate such as aluminum. It can be used as an undercoat agent for an aluminum substrate.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited by a following example, unless the summary is exceeded. First, the evaluation method and the raw materials used will be described.

(Evaluation method)
[Glass-transition temperature]
The constituent weight fractions of the constituent monomers a, b,... In the vinyl polymer are defined as Wa, Wb,..., And the glass transition temperatures Tga, Tgb of the homopolymers of the constituent monomers a, b,. In this case, the Tg value of the vinyl polymer that is a copolymer is obtained by the following formula.
1 / Tg = Wa / Tga + Wb / Tgb +

{Adhesion test}
As a base material, a bar coater no. 10 was used to coat the obtained composition so that the coating amount was 6 g / m ² (after drying). And after drying at 80 degreeC for 20 second, it dried at room temperature for 3 days.
A commercially available cellophane tape was applied to the coated surface of the obtained laminate, and the state when peeled off was evaluated according to the following criteria.
○: No peeling of coating film △: Part of coating film was peeled ×: Whole surface of coating film was peeled off

{Blocking evaluation}
In a state where the coated surface of the laminate obtained by the above-mentioned adhesion test was faced up, it was superposed on an uncoated base material (side that was not a mirror surface). On top of that, a load was applied so as to be 0.5 g / m 2 and the mixture was left at 50 ° C. for 24 hours. Then, it evaluated in the state when the laminated bodies were peeled off.
○: It was able to peel without resistance Δ: There was a little resistance when peeling ×: There was resistance when peeling

(raw materials)
[Polycarbonate diol]
-Kuraray Co., Ltd .: Kuraray polyol C-2090 ... 1,6-hexanediol / 3-methyl-1,5-pentanediol = 10/90 (molar ratio), OHV: 56 mgKOH / g, hereinafter, "C2090 ". “OHV” means a hydroxyl value (unit: mgKOH / g) measured by JISK 1557.

-Kuraray Co., Ltd .: Kuraray polyol C-2050 ... 1,6-hexanediol / 3-methyl-1,5-pentanediol = 50/50 (molar ratio), OHV: 56 mgKOH / g, hereinafter, "C2050 ".

-Ube Industries, Ltd. product: ETERNACOLL UH-CARB200 ... 1, 6- hexanediol 100%, OHV: 56 mgKOH / g, Hereinafter, it calls "U200."

[Carboxyl group-containing diol]
Dimethylolpropionic acid: manufactured by Mallinckrodt Chemical Inc., hereinafter referred to as “DPMA”.

[Polyisocyanate component]
• 4,4′-dicyclohexylmethane diisocyanate: manufactured by Sumitomo Bayer Urethane Co., Ltd .: Desmodur W, hereinafter referred to as “H12MDI”.

[Polymerization catalyst]
Dibutyltin dilaurate: Wako Pure Chemical Industries, Ltd .: Reagent, hereinafter referred to as “DBTBL”.
[Polymerization stabilizer]
Hydroquinone: Wako Pure Chemical Industries, Ltd .: Reagent, hereinafter referred to as “HQ”.

[Radically polymerizable monomer]
-Methyl methacrylate: Mitsubishi Rayon Co., Ltd., hereinafter referred to as "MMA".
・ Butyl acrylate: manufactured by Mitsubishi Chemical Corporation, hereinafter referred to as “BA”.

[Polymerization initiator]
Redox initiator: 7 wt% t-butyl hydroperoxide aqueous solution (hereinafter referred to as “H70”) and 1 wt% ascorbic acid aqueous solution (hereinafter referred to as “AsA”) were used.

[Basic compounds]
Triethylamine: Wako Pure Chemical Industries, Ltd., hereinafter referred to as “TEA”.

(Examples 1-2, Comparative Examples 1-3)
Each component of the preparation shown in Table 1 was added to a four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and the internal temperature was set to 50 ° C. Subsequently, each component of the additive shown in Table 1 was added, heated to 90 ° C., and reacted for 5 hours to obtain a urethane polymer.

TEA was added to the obtained urethane polymer solution by the amount shown in Table 1 to neutralize the carboxyl groups in this urethane polymer solution.
Subsequently, the water of the quantity shown in Table 1 was dripped over 15 minutes at 50 degreeC, and the milky white transparent dispersion liquid was obtained.

  Next, this dispersion was kept at 50 ° C., and at this temperature, H70 and AsA were added in the amounts shown in Table 1 to start polymerization of the radical polymerizable monomer. After completion of heat generation, the temperature was further raised to 80 ° C. and maintained for 2 hours to obtain an aqueous dispersion containing polyurethane and a vinyl polymer.

Claims (3)

In the method for producing an aqueous dispersion of polyurethane-vinyl polymer composite resin obtained by dispersing polyurethane (A) and vinyl polymer (B) in an aqueous medium,
The component (A) and the component (B) have the following characteristics:
By sequentially performing the following steps (a) to (d), the content of the component (B) per 100 parts by weight of the component (A) is 20 parts by weight or more and 400 parts by weight or less. A method for producing an aqueous dispersion of a polyurethane-vinyl polymer composite resin, wherein an aqueous dispersion of the composite resin is produced.
-(A) component: The diol component which comprises this (A) component contains the polycarbonate diol whose structural formula is shown by following formula (1), and a number average molecular weight is 500-5000,
The amount of the polycarbonate diol used is 40 wt% or more and 90 wt% or less of the entire diol component,
And in this polycarbonate diol, the content of those having a hexamethylene unit as the linking group R in the following formula (1) is 40 mol% or more of the whole diol component,
On the other hand, the polyol which has a carboxyl group is included as a diol component which comprises (A) component.

(In the formula, n represents a positive integer. R represents an alkylene group having 2 to 12 carbon atoms.)
-(B) component: Glass transition temperature (Tg) is 20 degreeC or more and 80 degrees C or less.
Step (a): A step of producing a polyurethane containing a carboxyl group by reacting a diol component containing the polycarbonate diol with a polyisocyanate in the presence of a radical polymerizable monomer having no active hydrogen. Step (b): Step of neutralizing the carboxyl group with a basic compound Step (c): Step of adding water to disperse the polyurethane and the radical polymerizable monomer in water to obtain an aqueous dispersion Step (d): Step of obtaining a vinyl polymer by polymerizing the radical polymerizable monomer.   The manufacturing method of the polyurethane-vinyl polymer composite resin aqueous dispersion of Claim 1 used as a part of undercoat agent.   The method for producing an aqueous polyurethane-vinyl polymer composite resin dispersion according to claim 2, wherein the undercoat agent is used for an aluminum substrate.