JP3417624B2 - Polyol and polyurethane composition using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyol mainly for urethane using a transesterification product of polymerized castor oil as a raw material. It also relates to a polyurethane composition using the polyol.

[0002]

[Prior art]

<Acrylic urethane paint> Urethane paint using acrylic resin (acrylic polyol) as a polyol component and polyisocyanate component as a curing agent is used as a paint for automobile repairs, floors, building exteriors, and mechanical devices. . Here, the acrylic resin has a hydroxyl value of 15 to 10
Although about 0 is used, since the acrylic resin itself has a high viscosity, about 40 to 60% of a solvent is added to dilute it.

<Castor oil as a polyol for urethane> As is well known, castor oil is a triglyceride of a fatty acid whose main component is ricinoleic acid, and less than 90% of its constituent fatty acids are ricinoleic acid, and the remaining fatty acids. Most of these have no OH group. Therefore, it can be said that castor oil is a polyol having about 2.7 OH groups in one molecule. Castor oil is commonly used for the purpose of polyurethane production by utilizing the properties of the polyol.

One of the uses of castor oil as a polyol for urethane is disclosed in JP-A-1-287182.
That is, in this publication, castor oil (a) 20 to 80% by weight
And 5 to 25% by weight of a polyhydric alcohol (b) having a valence of 3 or more are transesterified, and then ε-caprolactone (c) 10
Number average molecular weight 1000 obtained by reacting 70% by weight
Hereinafter, a solventless two-component type urethane coating resin composition containing a polyol (A) having a hydroxyl value of 150 to 350 and a polyisocyanate (B) as essential components is shown.

[0005]

[Problems to be Solved by the Invention]
There is a strong demand for high solidification of acrylic urethane paints, but high solidification is not easy because there is a limit to lowering the viscosity of acrylic resin (acrylic polyol). Although a method using a reactive diluent has been tried, it cannot be said that the excellent physical property balance of the acrylic urethane coating is fully utilized.

The present inventors have examined using the polyol disclosed in JP-A-1-287182 in combination with an acrylic resin (acrylic polyol). However, the transesterification reaction product of castor oil and polyhydric alcohol Since the polyol obtained by reacting with caprolactone is based on castor oil, its molecular weight cannot be increased, so that the hardness of the coating film tends to be insufficient and various physical property balances tend to be impaired.

Under the above circumstances, the present invention provides a novel polyol, particularly a urethane polyol suitable for the purpose of a reactive diluent for a high solid type acrylic urethane coating, and further, the urethane polyol. An object of the present invention is to provide a polyurethane composition (particularly, a polyurethane composition for acrylic urethane coating) which can be made into a high solid by using the above.

[0008]

The polyol of the present invention comprises:
A polyol having a hydroxyl value of 100 to 400 obtained by reacting a transesterification product of polymerized castor oil with caprolactone at a weight ratio of 90:10 to 50:50, particularly a polyol for urethane.

The polyurethane composition of the present invention comprises the above polyol for urethane and polyisocyanate.

Furthermore, the polyurethane composition for an acrylic urethane coating composition of the present invention comprises the above-mentioned urethane polyol, acrylic polyol and polyisocyanate.

The present invention will be described in detail below.

<Polyol> The polyol of the present invention is obtained by reacting a transesterification product of polymerized castor oil with caprolactone.

The polymerized castor oil is obtained by heating and reacting 100 parts by weight of castor oil with 1 to 20 parts by weight of organic peroxide. When the proportion of the organic peroxide is too small, the degree of polymerization becomes low and the intended polymerization purpose cannot be achieved. On the other hand, when it is too large, the side reaction becomes excessive and the quality of the polymer becomes poor.

Examples of the organic peroxide include di-t.
-Butyl peroxide, t-butyl cumyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, cumene hydroperoxide, t-butyl perbenzoate and the like can be mentioned. Of these, di-t-butyl peroxide is particularly useful and practically limited thereto.

At the time of charging, castor oil and organic peroxide may be charged all at once, but in order to control the reaction, first castor oil is charged to the reactor, and then organic peroxide is added dropwise thereto. Is more advantageous.

The reaction temperature is preferably 110 to 180 ° C. When the temperature is lower than 110 ° C., it is difficult to obtain the target polymer because the reaction rate is slow. On the other hand, when it exceeds 180 ° C., a side reaction occurs and the target polymer is generated. The quality will be inferior.

As a typical reaction operation, a caster oil is charged into a reactor equipped with a stirrer, a thermometer, a reflux condenser, a receiver, an inert gas introducing pipe, a dropping funnel and the like, and the temperature is 110 ° C. to 1 ° C.
Keeping the temperature at 80 ° C., preferably 120 to 160 ° C., while blowing an inert gas such as nitrogen gas, the organic peroxide is added thereto.
Add dropwise over 0.2 to 2 hours, and then add temperature 11
A method is employed in which the reaction is continued for 1 to 6 hours while the decomposed product is collected in a receiver at 0 to 180 ° C, preferably 120 to 170 ° C. A light-colored transparent polymer is typically obtained by the above reaction.

The viscosity of the polymerized castor oil thus obtained is 1500 to 100000 cps / 25 ° C., especially 2000.
It is desirable that the temperature is 20,000 cps / 25 ° C. If the viscosity of the polymerized castor oil is too low, the physical properties such as the hardness of the coating film will deteriorate, and if the viscosity is too high, the performance as a reactive diluent will be impaired.

The method for producing the polymerized castor oil is described in detail in JP-A-63-172781 filed by the present applicant.

The transesterification reaction product of polymerized castor oil is obtained by reacting the polymerized castor oil with a polyol. The reaction ratio of both is 60-9 for polymerized castor oil.
It is often 5% by weight and the polyol is 5-40% by weight.

Here, as the polyol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, tripropylene glycol,
Polypropylene glycol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol,
1,6-hexanediol, neopentyl glycol,
Trimethylolpropane, ditrimethylolpropane,
Examples thereof include trimethylolethane, glycerin, diglycerin, pentaerythritol, dipentaerythritol, and polyester polyols, and it is particularly preferable to use at least part of a trivalent or higher valent polyol.

The transesterification reaction is usually carried out in the presence of a catalyst such as alkali hydroxide, alkali metal alcoholate, sodium carbonate, calcium acetate, zinc acetate or litharge.
It is carried out under the conditions of 80 to 260 ° C. and 15 minutes to 6 hours.

The reaction ratio between the transesterification product of polymerized castor oil and caprolactone is 90:10 to 5 by weight.
It is set to 0:50 (especially 80:20 to 60:40). When the proportion of caprolactone is less than this range, the physical properties of the coating become poor because the molecular weight does not increase and the reactivity is slow, while when the proportion of caprolactone is greater than this range, the reaction product crystallizes, and The molecular weight becomes too high and the viscosity becomes high, so that it cannot serve as a reactive diluent. The reaction of an appropriate amount of caprolactone improves the water resistance,
It contributes to the adjustment of the molecular weight and the hydroxyl value and the imparting of flexibility to the formed coating film.

The hydroxyl value of the polyol thus obtained must be in the range of 100 to 400.
When the hydroxyl value is less than 100, although the molecular weight is increased, the hydroxyl value is low, so that the coating film hardness is lowered and the physical properties are deteriorated.
On the other hand, when the hydroxyl value exceeds 400, the molecular weight does not increase and the reaction is delayed, resulting in deterioration of physical properties such as impact resistance and flex resistance, and the amount of polyisocyanate increases, which is uneconomical.

The resulting polyols are particularly useful as urethane polyols, especially as reactive diluents for acrylic urethane coatings, but can also be used as urethane polyols for other purposes of polyurethane production.

<Polyurethane Composition> A polyurethane composition is prepared by blending the above polyol for urethane with polyisocyanate. When preparing a polyurethane composition for an acrylic urethane coating, a polyol for urethane and an acrylic polyol are used together and blended with polyisocyanate.

As the polyisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate or its hydrogenated product or carbodiimide modified product, naphthalene diisocyanate, xylylene diisocyanate,
Various polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, phenylene diisocyanate, isocyanurate, and adducts with these polyhydric alcohols (trimethylolpropane etc.) are used. Among these,
Yellowing-free polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate are important.

Examples of the acrylic polyol include OH group-containing (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, styrene, various (meth) acrylates, and (meth).
A copolymer with a monomer such as acrylic acid is used.

When the above urethane polyol and acrylic polyol are used in combination, the ratio of the two is often about 5:95 to 75:25 by weight.

The blending ratio of the above-mentioned urethane polyol (or acrylic polyol) and polyisocyanate is preferably such that the equivalent ratio of NCO / OH is 0.8 to 1.4 because sufficient curing can be achieved. .

In preparing the polyurethane composition, a pigment and an organic solvent are usually blended, and various additives are further blended, if necessary.

The polyurethane composition thus obtained can be used in various applications such as paints, moldings, encapsulants, inks and adhesives, but is particularly useful for applications of acrylic urethane paints. Is.

<Other Uses> The polyol of the present invention is useful as a polyol for polyurethane as described above, but can also be used as a reactive diluent for acrylic melamine coatings.

[0034]

The polyol of the present invention, that is, the polyol having a hydroxyl value of 100 to 400 obtained by reacting the transesterification reaction product of polymerized castor oil with caprolactone has a high crosslink density because polymerized castor oil is used as a raw material. There is. Therefore, when this is used as a polyol for urethane to form a polyurethane, the hardness is not insufficient and the balance of physical properties is not impaired.

This urethane polyol is suitable for the purpose of a reactive diluent for acrylic urethane coatings,
In addition to achieving high solidity of this coating material, since the urethane polyol is oil-modified, the pigment dispersibility is also improved.

[0036]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, “parts” means parts by weight.

<Production of Polyol> Example 1 52 parts of polymerized castor oil (“POLYCASTOR60” manufactured by Ito Oil Co., Ltd.) having a viscosity of 17450 cps / 25 ° C., 13 parts of trimethylolpropane and a small amount of catalyst (sodium methylate).
0.3 part or 0.03 part of lithium hydroxide, which is the same in the following examples) was charged into a reactor, the temperature was raised with stirring while blowing nitrogen gas, and the transesterification reaction was carried out at 250 ° C. for 3 hours. Then, the temperature was lowered to 200 ° C., 35 parts of ε-caprolactone was added, and the reaction was carried out at this temperature for 5 hours.
This gives a hydroxyl value of 251, a viscosity of 3700 cps / 25 ° C,
A polyol having a nonvolatile content of 100% was obtained.

Example 2 45 parts of polymerized castor oil (“POLYCASTOR60” manufactured by Ito Oil Co., Ltd.) having a viscosity of 17450 cps / 25 ° C., 8 parts of trimethylolpropane and polyester polyol (“Placcel L-220AL manufactured by Daicel Chemical Industries, Ltd.”) )) 12 parts and a small amount of catalyst were charged into the reactor, the temperature was raised with stirring while blowing nitrogen gas, and the transesterification reaction was carried out at 250 ° C. for 3 hours. Then add 35 parts of ε-caprolactone,
The reaction was carried out at 200 ° C. for 5 hours. This gives a hydroxyl value of 1
A polyol having a viscosity of 77, a viscosity of 3590 cps / 25 ° C. and a nonvolatile content of 100% was obtained.

Examples 3 to 6 Example 1 except that the charged raw materials and the charged ratio were variously changed.
A polyol was produced in the same manner as in .about.2.

Comparative Examples 1 to 3 Example 1 except that the charged raw materials and the charged ratio were variously changed.
A polyol was produced in the same manner as in .about.2.

Table 1 shows conditions and results of Examples 1 to 6 and Comparative Examples 1 to 3. The abbreviations in Table 1 have the following meanings. P-CO: Polymerized castor oil with a viscosity of 17450 cps / 25 ° C CO: Castor oil TMP: Trimethylolpropane 220AL: Polyester polyol "Placcel L-220AL" PE: Pentaerythritol Digly: Diglycerin CHDM: 1,4-Cyclohexanedimethanol εCL : ε-caprolactone

[0042]

[Table 1] Practical example Comparison Comparative example 1 2 3 4 5 6 1 2 3 Raw material and parts Polyol P-CO 52 45 46 52 52 52 31 52 CO 51 TMP 13 8 19 8 43 14 220AL 12 PE 13 Digly 13 CHDM 13 Caprolactone εCL 35 35 35 35 35 35 61 5 35 Properties of reaction product Hydroxyl value 251 177 312 297 258 184 150 622 260 Viscosity 3700 3590 2740 6550 5470 2960-7360 1440 Appearance Transparent Transparent Transparent Transparent Transparent Transparent Transparent Solidified Transparent Transparent (Note) The unit of viscosity is cps / 25 ° C.

<Manufacture and Evaluation of Acrylic Urethane Paint><Manufacture of Paint> The polyols obtained in Examples 1 to 3 and Comparative Examples 2 to 3 and acrylic polyol having a nonvolatile content of 60% (manufactured by Dainippon Ink and Chemicals, Inc.) "Acridic BU-955"), a pigment (titanium white, "Taipec CR-95" manufactured by Ishihara Sangyo Co., Ltd.) and a solvent (xylene), and then hexamethylene diisocyanate 3
Quantum (“Coronate H” manufactured by Nippon Polyurethane Industry Co., Ltd.
X ”) is blended so that NCO / OH = 1/1,
A resin composition for acrylic urethane coating was prepared. Further, as a reference example, an experiment was also conducted on a formulation in which the above-mentioned urethane polyol was omitted.

<Evaluation> The viscosity of the coating resin composition prepared above was measured, and the composition was applied on a tin plate having a thickness of 0.3 mm by a bar coater (Rod No. 26, wet 59.4 μm), The physical properties of the coating film after drying and standing at 25 ° C. for 7 days were measured. The conditions and results are shown in Table 2. The evaluation method of coating film physical properties is based on JIS K-5400. Among the physical properties of the coating film, regarding bending resistance, impact resistance, boiling water resistance, and stain resistance,
The evaluation was carried out under the following conditions, and was evaluated as ⊚ (good enough for practical use), ◯ (almost good), Δ (somewhat unsatisfactory), and × (unsatisfactory).・ Bending resistance: Mandrel diameter 2 mm ・ Impact resistance: Weight height 50 cm, Shooting die radius 6.35 mm,
Weight mass 1000g-Boiling water resistance: Immersion time 7 hours-Stain resistance: Contamination material Oil pen (black / red), left for 18 hours.

[0045]

[Table 2]                               Paint manufacturing example 1 2 3 4 5 6 7 First liquid combination prescription (part)   Polyol component     Obtained in Example 1 10     Obtained in Example 2 10     Obtained in Example 3 10     Obtained in Comparative Example 2 10     Obtained in Comparative Example 3 10     Acridic BU-955 48 48 48 48 48 63 58   Pigment (white titanium) 30 30 30 30 30 30 28   Solvent (xylene) 12 12 12 12 12 7 14 1st liquid viscosity (cps / 25 ℃) 440 454 436 514 400 1290 410 1st liquid solvent amount (%) 31.2 31.2 31.2 31.2 31.2 32.2 37.2 Second liquid prescription   Coronate HX (part) 18 16 20 31 19 12 11 Viscosity after mixing 1 and 2 liquids (cps / 25 ℃) 705 686 708 845 652 1884 666 Solvent amount after blending 1 and 2 liquids (%) 26.4 26.9 26.0 23.8 26.2 28.8 33.5 Coating film properties   Dry film thickness (μm) 23 23 26 26 24 22 21   Coating film hardness (pencil hardness) H H H H HB H H   Adhesion (cross-cut test, n / 100) 100 100 100 100 100 100 100   Flex resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎   Impact resistance ◎ ◎ ◎ × × ◎ × ×   Boiling resistance ◎ ◎ ◎ ◎ ◎ ◎ × ×Contamination resistance ◎ ◎ ◎ ◎ ◎ △ ◎ ◎

From Table 4, acrylic urethane paints using the polyols for urethane of the Examples (Paint Production Examples 1 to 3)
It can be seen that is highly solid and is satisfactory in all of the coating film hardness, adhesion, flex resistance, impact resistance, boiling water resistance, and stain resistance. On the other hand, in the paint production examples 4 to 7, the physical properties of the coating film are not well balanced, the paint production example 4 requires a large amount of expensive polyisocyanate, and the paint production example 5 shows the coating film hardness. It can be seen that coating composition example 6 has a high compounding viscosity and coating composition example 7 is disadvantageous in terms of high solidification.

In addition, in the coating material manufacturing examples 1 to 3 in Table 4,
Although the amount of the solvent after the 1 and 2 liquids are mixed is set to a slightly high level of 26 to 27%, the viscosity after the 1 and 2 liquids are mixed is, for example,
Since sufficient operability can be obtained for practical use even at about 000 to 1200 cps / 25 ° C, the amount of solvent when preparing the first liquid should be reduced to about 20% or less after mixing the first and second liquids. Is easy and the desired high solidification is achieved.

[0048]

The polyol of the present invention has clear properties, and is a urethane polyol for polyurethane,
Especially, it is excellent as a reactive diluent for acrylic urethane coatings.

When this polyol is used as a reactive diluent for an acrylic urethane coating, it is possible to obtain a high solid and to have a practically excellent coating film physical property.

Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 18/42 C08G 63/00-63/91 C09D 175/04-175/16

Claims (5)

(57) [Claims] 1. A polyol having a hydroxyl value of 100 to 400 obtained by reacting a transesterification product of polymerized castor oil and caprolactone at a weight ratio of 90:10 to 50:50. 2. The polyol according to claim 1, which is a polyol for urethane. 3. The polyol according to claim 2, which is a reactive diluent for an acrylic urethane coating. 4. A polyurethane composition comprising the polyol according to claim 2 and a polyisocyanate. 5. A polyurethane composition for an acrylic urethane coating, which comprises the polyol according to claim 2, an acrylic polyol and a polyisocyanate.