JP6026859B2 - Antifoaming improver for waterborne antifoaming agent - Google Patents

Description

  The present invention aims to provide an improved antifoaming property for an aqueous coating antifoaming agent, which is intended to impart an improved antifoaming property to foams generated during aqueous coating production or painting by adding a small amount to the aqueous coating material. It relates to the agent.

  Antifoaming agents for water-based paints (see Non-Patent Documents 1 and 2) include (1) an oil type in which an antifoaming component is dispersed in mineral oil (Patent Document 1), and (2) a highly hydrophobic and oily type. Type of activator (Patent Documents 2 to 7), (3) Emulsion type (Patent Documents 8 to 13) in which an antifoam component (higher alcohol, ester, silicone oil, etc.) is emulsified and dispersed in water, (4) Oil compound type (Patent Documents 14 to 20), (5) Self-emulsifying type antifoaming agent (Patent Document 21), (Follow alcohol, ester, silicone oil, etc.) blended with fine powder such as silica powder 6) An antifoaming agent (Patent Document 22) in which a vinyl polymer is uniformly dissolved in an activator and a solvent.

  The defoamer is characterized by its defoaming properties: oil type is generally defoaming, activator type is defoaming, emulsion type is degassing, and oil compound type is versatile regardless of oily water, self-emulsifying type It is said that the type has a long defoaming effect, and the vinyl polymer dissolution type has an excellent defoaming effect for baking paints.

JP 2006-87966 A JP-A-9-117608 JP-A-9-117609 JP-A-11-244609 JP2000-300907 JP 2003-265904 A JP 2006-068678 A JP-A-6-39207 JP2000-300907 JP2005-13894 JP 2005-169271 A JP 2006-95506 A JP 2006-305461 A JP-A-8-239690 JP-A-10-286404 JP-A-10-323505 JP2003-170005 JP-A-2005-270890 JP-A-2005-279565 JP 2006-320837 A JP2007-21316 Tokuto-04526584

Aqueous paint and coating technology Technical Information Association (1992) pp. 167-181 H. Tatsuno, S. Ando, J. Phys. Chem., Part B, 110 (51), 25751-25760 (2006)

  However, among the antifoaming agents, silicone oil and oil compound type antifoaming agents are high-grade furniture paints that require high gloss in order to cause defects such as repellency and pinholes in the dried coating film. Refrained from plastic paints for home appliances and automotive paints. Instead, it is known that if a fluorocarbon solvent with low surface tension is used, the effect of breaking bubbles in the coating solution with a small addition is high, but there is a possibility of destroying the ozone layer, It is pointed out that the greenhouse gas is several hundred to several tens of thousands times that of carbon dioxide, and it is a compound that is difficult to use in paints where solvents are volatilized. Accordingly, it has not been common for water-based paints used as environmentally friendly paints to use fluorocarbon solvents.

  Therefore, the object of the present invention is to be used for applications requiring high appearance, which was not possible with conventional antifoaming agents for water-based paints. It is to provide an antifoaming agent for water-based paints.

In Non-Patent Document 2, Ando et al. Have proved that perfluorocarbons having 9 and 20 carbon atoms are included in β-cyclodextrin by measurement of ¹⁹ F nuclei by solid-state NMR. That is, it is suggested that the structure of the β-cyclodextrin inclusion compound does not change and the fluorocarbon does not volatilize even at temperatures above the boiling point of these fluorocarbons.

  As a result of various studies, the present inventors have reached the present invention. That is, according to the present invention, at least one compound included in the following (1) to (3) is blended in an existing antifoaming agent for water-based paints as an antifoaming improver, so that An antifoaming agent for water-based paints in which fluorocarbon does not volatilize can be provided.

Typical examples of existing antifoaming agents for water-based paints include those composed of a mixture of polyalphaolefin, polybutadiene, polybutene, polyisoprene, polyvinyl ether, polyisoethylene stearate polyoxyethylene hydrogenated castor oil, and a solvent.
(1) A compound in which a perfluorocarbon having 6 to 18 carbon atoms is included in β-cyclodextrin or a modified product thereof.
(2) A compound in which a hydrofluorocarbon having 6 to 18 carbon atoms is included in β-cyclodextrin or a modified product thereof.
(3) A compound comprising a hydrofluoroether having 6 to 18 carbon atoms in β-cyclodextrin or a modified product thereof.

According to the present invention, at least one of the following incorporated compounds (1) to (3) is added in an amount of 1 to 20% by weight per 80 to 99% by weight of the antifoaming agent for water-based paint, and the total of both is 100 % by weight. By blending with the antifoaming agent for water-based paint so as to be%, it is possible to provide an antifoaming agent for water-based paint in which the blended fluorocarbon solvent does not volatilize.
(1) A compound in which a perfluorocarbon having 6 to 18 carbon atoms is included in β-cyclodextrin or a modified product thereof.
(2) A compound in which a hydrofluorocarbon having 6 to 18 carbon atoms is included in β-cyclodextrin or a modified product thereof.
(3) A compound comprising a hydrofluoroether having 6 to 18 carbon atoms in β-cyclodextrin or a modified product thereof.

  The antifoaming agent for water-based paints formulated with these can effectively eliminate the foam generated during paint production, painting, drying and baking without volatilizing the fluorocarbon in the atmosphere. .

  The best mode of the present invention will be described below.

  Since the fluorocarbons (fluorinated solvents) used in the present invention are included in β-cyclodextrin or a modified product thereof, the number of carbon atoms is limited. If the carbon number is less than 5, it will not be included in β-cyclodextrin or its modified product, and will volatilize when the temperature rises. If the number of carbon atoms is greater than 18, it cannot be uniformly dispersed in the coating solution, and therefore, when formed into a coating film, creases and dents are generated. Further, β-cyclodextrin or a modified product thereof used for preparing the inclusion compound is essential, and inclusion compound cannot be prepared with α-cyclodextrin or γ-cyclodextrin.

  Commercially available β-cyclodextrin or a modified product thereof can be used as it is. For example, β-cyclodextrin is β-cyclodextrin sold by Tokyo Kasei and Wako Pure Chemical Industries as a reagent, β-100 sold by Shimizu Minato Sugar Co., Ltd., CAVAMAX sold by Cyclochem Co., Ltd. (R) W7 Food etc. can be used. Further, as the β-cyclodextrin modified product, a modified β-cyclodextrin of a type in which the low water solubility of β-cyclodextrin is improved is particularly useful. For example, 2,6-di-O-methyl-β-cyclodextrin sold as a reagent by Tokyo Kasei and Wako Pure Chemical Industries, 2-hydroxyethyl-β-cyclodextrin sold by Wako Pure Chemical Industries, 2-hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, methyl-β-CD sold by Shimizu Minato Sugar Co., Ltd., G2-β-CD, CAVASOL (R sold by Cyclochem, Inc. ) W7 M etc. can be used.

  Perfluorocarbons used in the present invention include perfluorohexane, perfluoroheptane, perfluorooctane, perfluorononane, perfluorodecane, perfluoroundecane, perfluorododecane, perfluorotetradecane, perfluorohexadecane, perfluoro. Examples include octadecane.

  The hydrofluorocarbons used in the present invention include 1H, 1H, 1H, 2H, 2H-perfluorooctane, 1H, 1H, 1H, 2H, 3H-perfluorononane, 1H-perfluoroundecane, 1H, 1H, 2H, 2H-perfluorododecane, 1H, 1H-perfluorotetradecane, 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorooctane, etc. It is done.

  The hydrofluoroethers used in the present invention include 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4- (trifluoromethyl) -pentane, Examples include 1,1,1,2,3,3-hexafluoro-4- (1,1,2,3,3,3-hexafluoropropoxy) -pentane.

The compounding quantity of the compound which included fluorocarbons in (beta) -cyclodextrin or its modification | denaturation to the antifoamer for water-based paints is 1 to 20 weight% per 80-99 weight% of this antifoamer , and both total is 100 weight % , Preferably 3 to 10% by weight per 90 to 97% of the antifoaming agent. If the blending amount is less than 1% by weight, sufficient defoaming performance cannot be exhibited. Moreover, even if it mix | blends more than 20 weight%, the defoaming effect hardly changes and it is useless in cost, and it becomes difficult to obtain a uniform product.

  A paint suitable for use in the antifoaming agent for water-based paints formulated with the antifoaming improver of the present invention is a paint that requires a high appearance. When the antifoaming agent is added to, for example, an aqueous base paint for automobiles, an aqueous intermediate paint for automobiles, an aqueous primer paint for automobiles, an aqueous paint for high-grade furniture, an aqueous paint for plastics, etc. Gives sufficient defoaming properties when painting and drying, and at the same time prevents the occurrence of coating defects such as armpits.

  The timing of adding the antifoaming agent for water-based paints containing the antifoaming property improving agent of the present invention to the paint is arbitrary, and it can be added either in the process of kneading the pigment or after the paint is produced. In particular, the antifoaming agent for water-based paints formulated with the antifoaming property improving agent of the present invention is superior to conventional ones in non-silicone type antifoaming agents because it is superior in defoaming properties of entrained foams. It is also suitable as an antifoaming agent.

  The amount of the antifoaming agent for water-based paint blended with the antifoaming property improving agent of the present invention varies depending on the kind of resin of the paint, the blending composition of the pigment, etc., but is usually 0.1% relative to the paint vehicle in terms of solid content. -10% by weight, preferably 1-5% by weight.

  If the amount added is less than 0.1% by weight, sufficient antifoaming properties cannot be provided. If it is added in an amount of more than 10% by weight, it may cause adverse effects such as poor adhesion between layers when coating is repeated, uneven coating on the top coating film, or water resistance of the coating film after drying. This is not preferable because it may cause

  Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

  In the following, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

Inclusion Compound Production Example 1
In a 1000 ml glass beaker, 10 g of β-cyclodextrin (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as β-CD) was weighed, and a saturated solution was prepared with 556 ml of distilled water. Thereto was added 4.2 g (equimolar to β-CD) of perfluorononane (manufactured by Wako Pure Chemical Industries, Ltd.). Then, it stirred for 72 hours using the magnetic stirrer. Since the inclusion compound became insoluble in water, the produced inclusion compound precipitated. After 72 hours, the product was filtered using filter paper and dried at 80 ° C. in a dryer. The weight of the generated inclusion compound was measured and found to be 12.2 g. This means that about half of the added perfluorononane was included in β-CD.

  Then, it grind | pulverized finely using the mortar and the "inclusion compound 1" was obtained.

Inclusion compound production example 2
In a 1000 ml glass beaker, 100 g of β-CD was weighed and a slurry was prepared with 500 ml of distilled water. Thereto was added 30.7 g of 1H, 1H, 1H, 2H, 2H-perfluorooctane (manufactured by Asahi Glass Co., Ltd.) (equimolar to β-CD). Thereafter, the mixture was stirred at 12000 rpm for 2 hours using a homogenizer (manufactured by IKA: ULTRA-TURRAX). The produced inclusion compound was dehydrated with a drier set at 80 ° C. When the weight of the inclusion compound produced was measured, it was 112.9 g. This suggests that about half of the added hydrofluorocarbon was included.

  Then, it grind | pulverized finely using the mortar, and "inclusion compound 2" was obtained.

Inclusion Compound Production Example 3
In a 1000 ml glass beaker, 100 g of β-CD was weighed and a slurry was prepared with 500 ml of distilled water. There, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4- (trifluoromethyl) -pentane (manufactured by 3M) 30.9 g (β- CD and equimolar). Thereafter, the mixture was stirred at 24000 rpm for 1 hour using a homogenizer (manufactured by IKA: ULTRA-TURRAX). The produced inclusion compound was dehydrated with a drier set at 80 ° C. When the weight of the inclusion compound produced was measured, it was 109.4 g. This suggests that about 1/3 of the added hydrofluorocarbon was included. 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4- (trifluoromethyl) -pentane has a molecular size compared to the fluorocarbons of Examples 1 and 2. It is thought that when it was heated, it partially slipped out of the inclusion body.

  Then, it grind | pulverized finely using the mortar, and "inclusion compound 3" was obtained.

Inclusion compound production example 4
In a 500 ml glass beaker, 150 g of methylated β-CD (trade name Methyl-β-CD: manufactured by Shimizu Minato Co., Ltd.) was weighed and dissolved in 150 ml of distilled water. Thereto, 38 g of perfluoroundecane (manufactured by 3M) (about 1/2 mol of methylated β-CD) was added. Then, it stirred at 12000 rpm for 1 hour using the homogenizer (the product made by IKA: ULTRA-TURRAX). After stirring, the clear solution became cloudy. It was a uniform suspension with no perfluorocarbon settling at the bottom of the beaker. This about 50% suspension solution was used as it was in the subsequent tests.

Inclusion Compound Production Example 5
In a 500 ml glass beaker, 150 g of methylated β-CD (trade name G2-β-CD: manufactured by Shimizu Minato Co., Ltd.) was weighed and dissolved in 100 ml of distilled water. Thereto was added 42 g of perfluorododecane (manufactured by 3M) (about 1/2 mol of methylated β-CD). Then, it stirred at 12000 rpm for 1 hour using the homogenizer (the product made by IKA: ULTRA-TURRAX). After stirring, the clear solution became cloudy. It was a uniform suspension with no perfluorocarbon settling at the bottom of the beaker. This about 65% suspension was used as it was in the subsequent tests.

Inclusion compound production comparative example 1
In a 1000 ml glass beaker, 10 g of β-cyclodextrin (hereinafter referred to as β-CD) was weighed, and a saturated solution was prepared with 556 ml of distilled water. Thereto was added 2.5 g of perfluoropentane (manufactured by Wako Pure Chemical Industries, Ltd.) (equimolar to β-CD). Then, it stirred for 72 hours using the magnetic stirrer. Since the inclusion compound became insoluble in water, the produced inclusion compound precipitated. After 72 hours, the product was filtered using filter paper and dried at 80 ° C. in a dryer. The weight of the generated inclusion compound was measured and found to be 10.2 g. This suggests that the added perfluoropentane has volatilized.

  Then, it grind | pulverized finely using the mortar and "comparison (beta) -CD-1" was obtained.

Inclusion compound production comparative example 2
In a 1000 ml glass beaker, 100 g of β-CD was weighed and a slurry was prepared with 500 ml of distilled water. Thereto, 22.9 g of dotetracontafluoroicosane (C20F42) (1/4 mol of β-CD) was added. Then, using a pressure type homogenizer (manufactured by SMT Co., Ltd .: LAB2000), the mixture was stirred for 30 minutes at 200 ° C. under a pressure of 150 bar. The produced inclusion compound was dehydrated with a drier set at 150 ° C. The weight of the produced inclusion compound was measured and found to be 122.5 g. Since the boiling point of detetracontafluoroicosane is 320 ° C., it cannot be determined whether or not it has been included, but according to Non-Patent Document 1, it is included at a ratio of hydrofluorocarbon: β-CD = 1: 4. Conceivable.

  Then, it grind | pulverized finely using the mortar and "comparison (beta) -CD-2" was obtained.

Inclusion compound production comparative example 3
In a 500 ml glass beaker, 50 g of α-cyclodextrin (hereinafter referred to as α-CD) was weighed, 200 ml of distilled water was added and stirred while heating, and completely dissolved at about 30 ° C. Thereto, 25 g of perfluorononane (equimolar to α-CD) was added, and the mixture was stirred for 72 hours using a magnetic stirrer. Even after 72 hours, no inclusion compound was obtained, and perfluorononane separated and settled on the bottom of the beaker.

Inclusion compound production comparative example 4
In a 500 ml glass beaker, 100 g of γ-cyclodextrin (hereinafter referred to as γ-CD) was weighed, 200 ml of distilled water was added and stirred while warming, and completely dissolved at about 30 ° C. Thereto, 37.6 g of perfluorononane (equimolar to γ-CD) was added. Then, it stirred at 12000 rpm for 1 hour using the homogenizer (the product made by IKA: ULTRA-TURRAX). After stirring, the clear solution became cloudy. However, over time, it was observed that perfluorocarbons were sinking to the bottom of the beaker. About 40% of the suspension was shaken at the time of use and used as it was in the subsequent tests. “Comparative β-CD-4”

Formulation Examples 1 to 8 (Examples in which inclusion compounds are mixed with existing antifoaming agents for water-based paints)
Inclusion compounds 1 to 5 were mixed with the existing antifoaming agent at the ratio shown in Table 1 and stirred at 12000 rpm for 1 hour using a homogenizer (manufactured by IKA: ULTRA-TURRAX). The particle diameter of the included inclusion compound was 1 μm or less, and a uniform dispersion was obtained.

Formulation comparative examples 1-5 (example 1 which does not mix an inclusion compound)
The existing products shown in Table 2 were used in the paint test comparative examples.

Formulation comparative examples 6-9 (example 2 which does not mix an inclusion compound)
Test products containing the fluorocarbons shown in Table 3 were used as test comparative examples.

Formulation Comparative Examples 10-12 (compounding inclusion compound comparative example materials)
Test articles containing the inclusion compound production comparative materials shown in Table 4 were used as test comparative examples.

Measurement of heating residue The heating residue of all the prepared test products was measured. The measurement of the heating residue was performed based on JIS K 0067: 1992 chemical product weight loss and residue test method.

  1 g of a sample is quickly weighed in a metal evaporating dish whose weight is known in advance, and weighed with a precision chemical balance. Place in a hot air drying oven maintained at 105 ° C. ± 2 ° C. and heat for 3 hours. Then, it is taken out, allowed to cool to room temperature in a desiccator, and weighed again to measure the remaining amount in the metal evaporating dish. Three measurements were taken and the average value was taken as the heating residue value.

The heating residue was determined from the following equation.
A = (m ₂ / m ₁ ) × 100
A: heating residue
m ₂ : Remaining amount in metal evaporating dish (g)
m ₁ : sample weight (g)

  From the measurement of the residual heating, it was confirmed that the fluorocarbons included in the examples were values almost equal to the theoretical values assumed that the fluorocarbons do not volatilize. On the other hand, Comparative Example 6 to Comparative Example 9 and Comparative Example 12 except for Comparative Example 11 were measured to have a value lower by the numerical value of the blended fluorocarbon than the theoretical value assumed that the fluorocarbon was not volatilized. It is suggested that it has volatilized by measuring the heating residue. In Comparative Example 10, it is suggested that the fluorocarbon has already volatilized during the production, and only β-CD containing no fluorocarbon is blended. The boiling point of the fluorocarbon blended in Comparative Example 11 is 320 ° C., and it is considered that the fluorocarbon was not volatilized under the current measurement conditions.

Paint test example (defoaming test with water-based acrylic paint)
The water-based acrylic paint composition having the formulation shown in Table 6 was tested for defoaming properties.

(Create water-based acrylic paint)
The mill base formulation shown in Table 6 was uniformly dispersed using a lab disperser (High Flex Disperser SG2 manufactured by SMT Co., Ltd.) to prepare a mill base. Next, the obtained coating material was adjusted with 2-dimethylethanolamine so that the pH was 7.8, and then diluted with distilled water so that the viscosity was 30 seconds (20 ° C.) with Ford Cup # 4.

(Defoaming test in cans: Testing and evaluation of defoaming during paint preparation)
The antifoaming agents shown in Tables 1 to 6 were added to the prepared aqueous acrylic paint in an amount of 2% by weight based on the paint, and the resulting foam was stirred with a lab disper at a rotation speed of 4000 rpm for 3 minutes.

  One minute and five minutes after the completion of stirring, the specific gravity of the water-based paint entrained with foam was measured using a 100 ml specific gravity cup (manufactured by Dazai Equipment Co., Ltd.). It can be said that the greater the specific gravity, the higher the effect of breaking the entrained bubbles.

(Defoaming test during painting and drying)
The aqueous acrylic paint thus prepared was allowed to stand for 24 hours, and then the paint was applied to a tin plate having a size of 200 mm × 300 mm by air spray so that the film thickness after drying was 30 μm. After setting at room temperature for 1 minute, forced drying was performed in an oven at 100 ° C.

(Evaluation of antifoaming properties during painting and drying)
The evaluation of the defoaming property was evaluated in five stages from the “best” (5) to the “worst” (1) by visually observing the occurrence of flares and cissing.

  The results are shown in Tables 7 and 8.

  The armpit referred to here is a bubble generated in the forced drying coating film, and can be visually confirmed in the form of a bubble on the surface of the coating film. The term “repellency” used herein refers to a crater-like dent or a hole where the substrate can be directly seen on the surface of the coating film after drying.

Even when it was included in β-CD, improvement in the specific gravity recovery rate was observed when fluorocarbon was added.
Moreover, coating film defects such as repelling did not occur.

The blending of the fluorocarbon alone showed an antifoaming property comparable to that blended with the inclusion compound of the example.
Cyclodextrins that cannot contain fluorocarbons did not contribute to the defoaming effect.

Claims (1)

An antifoaming improver for a waterborne antifoaming agent,
(1) A compound in which a perfluorocarbon having 6 to 18 carbon atoms is included in β-cyclodextrin or a modified product thereof ,
(2) a compound containing a hydrofluorocarbon having 6 to 18 carbon atoms in β-cyclodextrin or a modified product thereof, and
(3) the number of carbon atoms is from a hydrofluoroether from 6 18 beta-cyclodextrin or at least one inclusion compounds were selected from the compounds subsumed in its modified product, digested per antifoaming 80-99 wt% An anti- foaming agent is added to the anti-foaming agent so that the total amount of the antifoaming agent and the antifoaming improving agent is 100 % by weight in a proportion of 1 to 20% by weight. Foam improver.