JPH08302134A - Vinyl chloride plastisol composition - Google Patents

Abstract

PURPOSE: To prevent a vinyl chloride plastisol composition from foaming and losing adhesion during being baked and enable recycling of a waste coating material discharged from a coating step. CONSTITUTION: This vinyl chloride plastisol composition comprises a vinyl chloride resin, a plasticizer, a filler containing a fine powder of a waste coating material and an adhesion promoter comprising a combination of an amino compound component containing active hydrogen atoms with a blocked isocyanate component in such amounts that the NA/NI ratio is 1.1-5.0 (wherein NA is the number of the active hydrogen atoms contained in the amino compound component, and NI is the number of the isocyanate groups contained in the blocked isocyanate component. Because the NA/NI ratio is specified, the coating film does not undergo foaming and loss of adhesion which occur when a fine powder of a waste coating material is contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride plastisol composition used as a sealing composition for automobile bodies and the like, an undercoat composition, a chipping resistant coating, and the like. The present invention relates to a vinyl chloride-based plastisol composition containing powder as a filler.

[0002]

2. Description of the Related Art Conventionally, for example, a steel plate joint portion or a steel plate edge portion of an automobile body after electrodeposition coating is water-tight or air-tight in order to improve the rust-preventive property before finishing coating. The sealing composition is applied and coated. Further, an undercoat composition or a chipping-resistant paint is applied to the lower floor of a vehicle body, a wheel house, or the like in order to improve rust resistance and chipping resistance.

The sealing or undercoating composition or the chipping-resistant coating composition has excellent rust resistance, can form a relatively thick coating film, and has excellent chipping resistance. For the reason, and also from the viewpoint of versatility and cost, a vinyl chloride-based plastisol composition has been conventionally generally used. This plastisol composition comprises a vinyl chloride resin consisting of a vinyl chloride homopolymer or a copolymer with vinyl acetate and the like as a main component and a plasticizer, and a filler and other additives added thereto. Is.

By the way, in such a vinyl chloride-based plastisol composition, since the vinyl chloride-based resin has high crystallinity, the adhesion (adhesion) of the coating film to the article to be coated tends to be relatively low. In particular, it tends to be difficult to obtain sufficient adhesiveness to a cationic electrodeposition coated surface. Therefore, the vinyl chloride-based plastisol composition used for this sealing or the like, in order to improve its adhesion,
An adhesion promoter is generally added as an additive.

As the adhesiveness-imparting agent, various types such as a polyamide type, an acrylic type, a blocked isocyanate type, etc. are known in addition to the epoxy resin type and the phenol resin type. And, among these, the adhesion-imparting agent that uses a polyamide, which is an amino compound containing active hydrogen (amino group), and a blocked isocyanate obtained by blocking the isocyanate group of a polyisocyanate compound with a blocking agent is most commonly used. ing. According to the combined system of the polyamide component and the blocked isocyanate component, the blocking agent is dissociated at the temperature during heating and baking,
The isocyanate group of the regenerated isocyanate compound reacts with the active hydrogen (amino group) of polyamide, polymerizes and cures, and develops adhesiveness. Therefore, it not only exhibits excellent adhesiveness even on a cationic type electrodeposition coated surface, but can exhibit adhesiveness under baking conditions of a relatively low temperature and also has excellent storage stability of the plastisol composition. ing.

The vinyl chloride-based plastisol composition containing an adhesiveness-imparting agent comprising such a combination system of a polyamide component and a blocked isocyanate component is, for example,
JP-A-56-24435 (Japanese Patent Publication No. 63-6103)
Japanese patent publication). Here, as the polyamide component, a reaction product of a fatty acid dimer and a polyamine (polyamide polyamine) is cited, and as the isocyanate compound of the blocked isocyanate component, an aliphatic or aromatic diisocyanate is cited. Further, in the one described in JP-B-59-52901, the isocyanate compound of the blocked isocyanate component is composed of a urethane prepolymer having an isocyanate group terminal of a polyol and an aliphatic or aromatic diisocyanate. Further, for example, JP-A-59-78279.
JP-A-59-131669 and JP-A-59-131669 disclose the combined use of an amino compound having a hydroxyl group as a polyamide component.

When a combination system of this polyamide component and a blocked isocyanate component is used as an adhesiveness-imparting agent, the mixing ratio of both components is such that the number of active hydrogen (amino groups) in the polyamide component and the blocked isocyanate component. As a general rule, the ratio should be equal to the number of the isocyanate groups (after dissociation), that is, the ratio such that the active hydrogen and the isocyanate groups have an equivalent ratio (molar ratio) of 1: 1. Is. As a result, when the plastisol composition is applied and baked and cured, theoretically no unreacted active hydrogen (amino group) or isocyanate group remains in the formed coating film. The blending weight ratio of the polyamide component and the blocked isocyanate component in the case where the number of active hydrogens and the number of isocyanate groups are the same, the active hydrogen (amino group) equivalent of the polyamide and the isocyanate group equivalent of the blocked isocyanate match the ratio, 56
(Molecular weight of potassium hydroxide) / amine value × 10 ⁻³ and 42
(Molecular weight of isocyanate group) / isocyanate content%
It is generally in agreement with the ratio of × 10 ^-2 . However, in reality, the isocyanate group is highly reactive and does not remain unreacted in the coating film.Therefore, the mixing ratio of the polyamide component and the blocked isocyanate component is such that the isocyanate group is slightly increased. (Ratio of active hydrogen is slightly lower), that is, the ratio is such that active hydrogen and isocyanate groups are in an equivalent ratio of 1: 1.0 to 1.2.

[0008]

As described above, a vinyl chloride-based plastisol composition is generally used as a sealing or undercoating composition for automobile bodies or the like, or as a chipping-resistant coating composition. Then, in this plastisol composition, as an adhesiveness-imparting agent, an amino compound containing active hydrogen (amino group), specifically, a combination system of polyamide and blocked isocyanate is generally used.

By the way, in recent years, from the viewpoint of resource protection and environmental protection, the recycling of various waste materials that have been disposed of as they are in the past has been reexamined. For example, waste plastic parts and the like are separately collected and recovered. It is being used. Recently, paint dregs discharged in the painting process of automobiles are also being recycled. The paint dregs are a collection of paints that did not adhere during the painting of automobiles, and are generally recovered as sludge from the washing water in the painting booth. The amount of this paint dregs produced when painting one vehicle is small,
When many vehicles are painted, this paint residue is produced in a relatively large amount. And the collected paint lees are
It is treated or cured to remove tackiness, dried and then pulverized into a fine powder to be reused as a dry fine powder of a paint meal.

This fine powder of paint meal has already been used in some cases as a filler for plastic materials. However, this paint meal consists of a mixture of differently colored paints and also contains other impurities, so that it has an overall grayish dark (dirty) shade. Therefore, even when this fine powder of paint meal is used as a filler for a plastic material, its use is naturally limited. Therefore, it has been considered to use this paint meal fine powder as at least a part of the filler in the above-mentioned sealing or undercoating composition, or a vinyl chloride plastisol composition used as a chipping-resistant paint. It was That is, these compositions or paints are applied to places where appearance is not a problem,
Further, since it is applied as an undercoat, the color tone of the paint meal is inconspicuous in appearance or does not appear on the surface.

However, when the fine powder of the paint meal was actually blended with the above vinyl chloride-based plastisol composition and tested, the coating film formed by applying this and baking-curing It was found that a new defect would occur. One of them, which was predicted to some extent, is a decrease in the adhesion of the coating film. Then, the decrease in the adhesiveness of the coating film was remarkable especially when the prepared plastisol composition was left for a long time. The other is that, unexpectedly, foaming occurs inside the coating film during baking. The foaming of the coating film is the same as in the case of decreasing the adhesion of the coating film, but it occurs similarly even when the types of the polyamide component and the blocked isocyanate component of the adhesion promoter are changed, and the amount of the coating lees powder is mixed. It became remarkable as the number was increased. And
When foaming occurs in the coating film as described above, the sealing property and the rust preventive property are remarkably lowered, and the chipping resistance is also lowered.

Therefore, in order to effectively reuse the paint dregs discharged in the coating process in this vinyl chloride-based plastisol composition for sealing, these problems, especially foaming of the coating film, can be solved. is necessary.

Therefore, an object of the present invention is to provide a vinyl chloride plastisol composition capable of preventing foaming of a coating film and deterioration of adhesion, and effectively reusing the coating meal.

[0014]

Means for Solving the Problems The present inventors have repeatedly conducted tests and studies on the foaming of the above-mentioned coating film and the deterioration of the adhesiveness which occur when a fine powder of paint meal is mixed with a vinyl chloride-based plastisol composition. As a result, the cause lies in the curing catalyst, free acid or carboxyl group contained in the paint meal, and these are the active hydrogen (amino group) of the amino compound (polyamide) which is one component of the adhesion promoter. It was speculated that this was because a salt or chelate was formed and its activity was reduced or inhibited. That is, by decreasing or inhibiting the activity of the amino compound, the polymerization and curing reaction between this and the blocked isocyanate which is the other component of the adhesion-imparting agent is suppressed, the adhesion of the coating film is reduced, and baking is also performed. It means that the dissociated isocyanate group reacts with water or a carboxyl group to generate CO ₂ and the coating film foams. Therefore, the present inventors further conducted tests and studies focusing on the blending ratio of the amino compound component and the blocked isocyanate component of the adhesiveness-imparting agent, and as a result, the blending ratio was determined to be the active hydrogen ( The number of (amino groups) is larger than the number of isocyanate groups in the blocked isocyanate in a certain range, so that the above foaming of the coating film and the deterioration of the adhesive property can be easily and effectively prevented. I found what I could do and confirmed it again.

That is, the vinyl chloride-based plastisol composition according to the present invention comprises a vinyl chloride-based resin and a plasticizer, a filler containing fine powder of paint meal, an amino compound component containing active hydrogen and a blocked isocyanate component. Adhesion-imparting agent comprising a combination system of the following: a ratio NA / NI of the number NA of active hydrogens contained in the amino compound component and the number NI of isocyanate groups contained in the blocked isocyanate component is 1.1. The adhesiveness-imparting agent mixed in a ratio of about 5.0 is an essential component.

The lower limit of this ratio NA / NI is preferably 1.2 or more, and more preferably 1.5 or more. The upper limit is 3.
It is preferably 2 or less, and more preferably 2.5 or less.

[0017]

In this way, the blending ratio of the amino compound component and the blocked isocyanate component in the adhesion promoter is
The number of active hydrogens (amino groups) contained in the amino compound component NA is set to be larger than the number of isocyanate groups contained in the blocked isocyanate component, NI. As described above, when the fine powder of the paint meal is used as a filler, it is possible to prevent the adhesion of the coating film from decreasing and prevent foaming. The reason for this is presumed as follows, including the decrease in the adhesiveness of the coating film and the cause of foaming.

That is, the paint meal contains various additives in addition to the resin base and the pigment. For example, a catalyst for curing the paint, such as a tin compound, stearic acid, salicylic acid type, etc. Contains acidic substances. The resin base itself also contains free carboxyl groups and the like. Furthermore, although the fine powder of the paint meal is dried, it contains a relatively large amount of water as compared with the usual filler such as calcium carbonate.

Therefore, the active hydrogen in the amino compound, that is, the amino group, forms a salt or chelate with the catalyst, acid or the like, and the activity thereof is reduced or inhibited. In addition, the amino compound itself has a poor compatibility, thereby causing a partial bias in the composition. in this way,
It is considered that the decrease in the adhesiveness of the coating film is due to the isocyanate compound dissociated from the blocked isocyanate being unable to satisfactorily polymerize and cure with the amino compound. And
This tendency becomes more remarkable as the amount of the fine powder of the paint meal is increased and the composition is left for a long time after preparation so that the amount of the catalyst and the like exuding from the paint meal increases. Incidentally, the reactivity of the isocyanate group with respect to active hydrogen is generally such that aliphatic NH ₂ > aromatic NH ₂ > primary OH>
The order is H ₂ O> secondary OH> tertiary OH> carboxyl group. Therefore, in the foaming of the coating film, as a result of the activity of the amino group of the amino compound being reduced or inhibited as described above, the isocyanate group reacts with the water content or the carboxyl group of the paint meal to generate carbon dioxide CO ₂ . It is thought to be caused by this.

In the present invention, the number of active hydrogens (amino groups) NA contained in the amino compound component is larger than the number of isocyanate groups NI contained in the blocked isocyanate component. Even if the activity of some of these is reduced or hindered by the catalyst contained in the paint meal, the polymerization-curing reaction between the isocyanate compound and the amino compound is well maintained. That is, the adhesion and foaming of the coating film are suppressed and prevented.

Although this is a speculation, it is considered that the adhesion and foaming of the coating film are prevented in this way, and it is also in agreement with the test results. Therefore, the more the number NA of active hydrogen (amino groups) contained in the amino compound component is larger than the number NI of isocyanate groups contained in the blocked isocyanate component, the more reliably the adhesion and foaming of the coating film are prevented. can do. Therefore, the ratio NA / NI is preferably 1.1 or more in general, although it depends on the amount of the fine powder of the paint meal and the amount of the adhesiveness imparting agent as a whole.
It is more preferably 2 or more. Further, it is most preferably 1.5 or more. However, this ratio NA / NI
Is too large and the active hydrogen (amino group) becomes excessive,
A large amount of unreacted amino groups or amino compounds remain in the coating film, which lowers the water resistance of the coating film and warps the adhesiveness. Therefore, the ratio NA / NI is generally 5.
It is preferably 0 or less, and more preferably 3.2 or less. Further, it is most preferably 2.5 or less.

The actual mixing ratio (weight) of the amino compound component and the blocked isocyanate component for adjusting the ratio NA / NI to a specific value is determined by the active hydrogen (amino group) equivalent EA of the amino compound component and the blocked isocyanate component. It can be easily determined from the isocyanate group equivalent EI of the component. That is, the weight part of the amino compound component is WA,
If the weight part of the blocked isocyanate component is WI,
Since NA: NI = WA / EA: WI / EI, the ratio N
When the value of A / NI is k, the ratio WA / WI is k · EA
/ EI (ratio WI / WA is EI / k · EA). Therefore, either WA or WI is first decided (generally WI
), Then the other may be calculated.

Here, the isocyanate group equivalent EI
Can be calculated on the basis of the estimated structural formula of the blocked isocyanate compound and is equal to 42 / NCO content (wt%) × 10 ^-2 . Further, the active hydrogen (amino group) equivalent EA is generally approximately equal to 56 / amine value × 10 ⁻³ , but it may be significantly different depending on the kind of the amino compound. It is calculated based on the estimated structural formula of the amino compound. The amino compound component and the blocked isocyanate component are used after being diluted with a plasticizer or a solvent in actual handling. Therefore, from the viewpoint of the metering property at the time of compounding, EI and EA can be calculated by including these plasticizers or solvents.

Hereinafter, each component of the vinyl chloride-based plastisol composition according to the present invention will be described in detail.
However, in this composition, fine powder of paint meal is blended as a filler, and basically the same as the conventional one except that the amino compound component and the blocked isocyanate component of the adhesiveness-imparting agent are used in a specific ratio. Is the same.

The vinyl chloride resin as the main component is a homopolymer of vinyl chloride or a copolymer with other vinyl monomers such as vinyl acetate, and these can be used alone or as a mixture. . The paste resin can be generally used as the vinyl chloride resin, but a blending resin or another resin can be used in combination therewith. The specific composition or formulation can be appropriately determined to obtain the desired coating film performance, but when the paste resin and the blending resin are mixed and used, the ratio is generally 4 by weight. / 1-2 / 3 is preferable. The blending ratio of the vinyl chloride resin in the whole composition is generally 1
0 to 40% by weight is preferable, and 20 to 30% by weight is more preferable.

As the plasticizer, any of those generally used for forming plastisols of vinyl chloride resins can be used. Examples of such a plasticizer include dioctyl phthalate (DOP), di-2-ethylhexyl phthalate, diisononyl phthalate (DINP), and other phthalate esters, di-2-ethylhexyl adipate (DOA), trioctyl trinoate. Aromatic and aliphatic di- and tricarboxylic acid esters such as literate (TOTN), sebacic acid ester, azelaic acid ester, or polyester, triphenyl phosphate,
Examples thereof include phosphoric acid esters such as tricresyl phosphate, epoxy plasticizers such as epoxidized soybean oil, and the like. These plasticizers can be appropriately selected and used in an appropriate amount according to desired physical properties such as viscosity and curability of plastisol. A part of the plasticizer can be changed to an organic solvent or the like. As such a solvent, a solvent having a boiling point as high as or higher than that of a plasticizer such as an aliphatic hydrocarbon or an aromatic hydrocarbon is preferable.

The fine powder of paint meal blended as a filler is
As described above, the paint meal discharged in the painting process is solidified or hardened, dried, and pulverized into a fine powder. And, the smaller the particle diameter, the more preferable from the viewpoint of the smoothness of the formed coating film. However, there is a limit to finely pulverizing, and the manufacturing cost becomes high. Therefore, the particle size of the fine powder of the paint meal is generally preferably about 30 to 150 μm. Further, the blending amount of these can be arbitrarily determined, and by blending a large amount, it can contribute to the protection of resources and the environment.
However, an excessively large amount of compound is not preferable because it tends to slightly reduce chipping resistance and the like. Therefore, the fine powder of the paint meal is preferably used as a part of the inorganic filler generally blended such as calcium carbonate, in a proportion of 50% by weight or less of the total filler, and the solid content of the entire composition. It is preferable to mix it in a ratio of about 1 to 30% by weight. However, this is not a limitation, and more blending is possible from the viewpoint of recycling the paint meal.

As the filler, a usual inorganic filler can be used together with the above-mentioned fine powder of paint meal. Thereby, the amount of the plastisol composition can be increased and the fluidity thereof can be adjusted, and at the same time, the formed coating film can be provided with appropriate physical properties such as strength. Examples of such fillers include calcium carbonate, magnesium carbonate, carbonates and sulfates of alkaline earth metals such as barium sulfate, mica, silica, talc, diatomaceous earth, kaolin and the like, each of which is independent. Or in an appropriate combination.

The adhesiveness-imparting agent comprises a combination system of an amino compound component containing active hydrogen and a blocked isocyanate component. Here, the amino compound acts as a dissociation accelerator for the blocked isocyanate and acts as a curing agent due to the amino group. Further, the amino group can also exhibit adhesiveness due to a hydrogen bond with the residual polar group (—NH ₂ , —OH, etc.) on the cationic electrodeposition coating film.
And, the amino compound component containing this active hydrogen,
Any amino compound or a mixture thereof may be used as long as it contains active hydrogen, and examples thereof include aliphatic diamine and aromatic diamine.
However, since aliphatic diamines and the like are volatile and toxic, polyamides, typically, as amino compounds,
A polyamide polyamine which is a reaction product of a polyamine and a polymerized fatty acid such as dimer acid or trimer acid obtained by thermally polymerizing an unsaturated fatty acid such as linoleic acid is preferable. Also,
According to such a polyamide, since the compounding equivalent is large,
It is easy to weigh and facilitates uniform blending in the plastisol composition.

The blocked isocyanate is a compound having 2 or 3 or more isocyanate groups in the molecule, which is blocked with a blocking agent. Examples of the polyisocyanate compound include aromatic diisocyanates such as tolylene diisocyanate (TDI), xylylene diisocyanate and diphenylmethane diisocyanate (MDI), aliphatic diisocyanates such as hexamethylene diisocyanate, hydrogenated TDI, isophorone diisocyanate and hydrogenated MDI. Examples thereof include alicyclic diisocyanate. And, although they can be used alone, since they have a high vapor pressure alone, they should be used as a buret or isocyanurate thereof, and as an adduct with a polyhydric alcohol (adduct). Is preferred.

Further, the polyisocyanate compound is more preferably an isocyanate group-terminated urethane prepolymer obtained by reacting a diisocyanate or polyisocyanate such as TDI with a polyol such as polyether polyol, polyester polyol or polymer polyol. . According to this, the stability is good and the adhesiveness to the cationic electrodeposition coated surface is excellent.
In addition, the molecular weight of this can be appropriately adjusted by changing the degree of polymerization thereof within a range that does not impair the compatibility with the plastisol composition, and is generally 600 to 250.
About 0 is preferable.

As a blocking agent for these isocyanate compounds, methyl ethyl ketoxime (ME
KO) and the like, active methylene compounds such as acetylacetone and acetoacetate, lactams such as ε-caprolactam, oxybenzoic acid esters, alkylphenols and the like can be used. Of these, MEKO is the most representative, and p-oxybenzoic acid-2-ethyl-hexyl ester or nonylphenol is particularly preferable because it has good compatibility with vinyl chloride resins and plasticizers.

The adhesiveness-imparting agent composed of the active hydrogen-containing amino compound component and the blocked isocyanate component can be added in an arbitrary ratio depending on the types and equivalents thereof. Generally, the proportion is 0.1 to 10 parts by weight based on the whole composition.

The vinyl chloride plastisol composition comprising these components contains a water absorbent, a
An anti-sagging agent, a leveling agent, a pigment, and other additives can be appropriately added and blended.

As the water absorbent, calcium oxide CaO can be generally used. Then, by adding this, it is possible to capture the residual water contained in the filler such as calcium carbonate or the vinyl chloride resin and prevent the foaming of the coating film at the time of baking. Further, when the plastisol composition is left as it is after application, it is possible to prevent foaming of the coating film during baking due to moisture absorption. Further, a relatively large amount of water contained in the paint meal can also be absorbed by this water absorbent.

The anti-sagging agent is used for adjusting the viscosity (thixotropic property) of the composition while keeping balance with other components to prevent sagging of the coating film. Colloidal ultrafine calcium carbonate. , Fine particle silica and the like can be preferably used also as a filler. On the other hand, the leveling agent is used to improve the leveling property of the coating film, and for example, a silicone resin or a high viscosity type or low viscosity type dimer acid-modified epoxy resin can be used. However, if too much is added, the sagging property deteriorates. Any pigment can be used as the pigment, but since the fine powder of the paint meal has a dark color, it is not suitable for a chromatic color pigment, and carbon black that also serves as an extender pigment is preferable. Furthermore, as other additives, epoxy-based stabilizers, metal soaps, inorganic acid salts of metals such as lead,
Examples thereof include plastisol stabilizers such as organometallic compounds and thickeners such as organic bentonite, and these can also be used if necessary.

Then, such a vinyl chloride plastisol composition can be applied to the surface of an object to be coated such as a vehicle body in an arbitrary thickness and application form by using, for example, a spray gun or a discharge gun. . However, since the paint lees are relatively large particles, the thickness thereof is preferably relatively thick, and in order to form a smooth coating film, it is preferably 500 μm or more. The bake-curing of the applied plastisol composition depends on the thickness of the coating film, etc.
After calcination at a temperature of 80-150 ° C or higher,
It can be performed in combination with baking drying of the intermediate coating material or the top coating material.

[0038]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples.

FIGS. 1 to 3 are tables showing the composition of the vinyl chloride-based plastisol compositions of the examples of the present invention and comparative examples and the evaluation test results. However, in FIG. 1, only a part of those Examples and Comparative Examples are shown, and in FIGS. 2 and 3 showing all Examples and Comparative Examples respectively, the main components (paint lees fine powder and adhesiveness Only the compounding composition of the imparting agent) is shown, and the description of other components is omitted.

[Preparation of Composition] The vinyl chloride-based plastisol compositions of Examples 1 to 12 of the present invention were prepared with the formulations (parts by weight) shown in FIGS. 1 to 3. For comparison, the vinyl chloride plastisol compositions of Comparative Examples 1 to 11 were also prepared. This plastisol composition is specifically applied as an undercoat composition, and improves chipping resistance and rust resistance between the electrodeposition coating film and the intermediate coating film of the automobile body. It is given to do. However, here, for the purpose of mainly an evaluation test, the compounding of additives which are usually used such as an anti-sagging agent and a leveling agent is omitted.

As shown in FIG. 1, the vinyl chloride-based plastisol compositions of these Examples and Comparative Examples all contain a vinyl chloride-based resin, a plasticizer, a filler, and an additive. In the examples, they are blended at the same blending ratio. That is, the vinyl chloride resin is 20 parts by weight, the plasticizer is 25 parts by weight, the filler is 30 parts by weight, and the additive is 4 parts by weight (in FIGS. 2 and 3, description of these components is omitted. .).

Here, as the vinyl chloride resin, specifically, a paste resin ("Zeon 38J" manufactured by Nippon Zeon Co., Ltd.) consisting of a copolymer of vinyl chloride and vinyl acetate is used.
An equal mixture of 10 parts by weight and 10 parts by weight of a resin for blending (“Zeon 121” manufactured by Nippon Zeon Co., Ltd.), which is also a copolymer of vinyl chloride and vinyl acetate, was used. DINP (diisononyl phthalate) was used as the plasticizer. As the filler, an equal amount mixture of 15 parts by weight of colloidal calcium carbonate (“CALCIES P”, manufactured by Kamishima Chemical Co., Ltd.) and 15 parts by weight of heavy calcium carbonate (“NS-100”, Nitto Koka Kogyo Co., Ltd.) was used. This colloidal calcium carbonate is also used as an anti-sagging agent. The additive is composed of 3 parts by weight of calcium oxide (CaO), which is a water absorbing agent, and 1 part by weight of a lead-based stabilizer.

Then, in this example, a fine powder of paint lees, which is a dry fine powder of the paint lees discharged in the painting step, was further blended as a filler to such a vinyl chloride plastisol composition. There is. Specifically, this paint meal fine powder is mainly composed of an intermediate top coat paint (acrylic-melamine type) discharged in the middle top coat paint process of an automobile body, and was discharged together with washing water in the paint process. The sludge of the paint meal is dried and hardened and then finely pulverized, and the average particle diameter is about 30 to 50 μm. In addition, in each of the examples, the paint meal fine powder is mixed in different amounts. That is, it is 4 parts by weight in Example 1, 14 parts by weight in Examples 3 and 9, and 9 parts by weight in other examples, which are about 5% by weight, about 14% by weight of the entire composition, And about 10% by weight, respectively. In Comparative Example, Comparative Example 1 corresponding to the conventional example was unblended, Comparative Example 2 was 4 parts by weight, Comparative Example 4 was 14 parts by weight,
In the other comparative examples, 9 parts by weight are each compounded.

As the adhesiveness-imparting agent, a combined system comprising two components of a blocked isocyanate component and a polyamide component which is an amino compound containing active hydrogen (amino group) is used. Here, as the blocked isocyanate, three types of urethane-based blocked isocyanates having different isocyanate group equivalents (blocked urethane prepolymers), that is, urethane prepolymers having a diisocyanate compound and a polyol and having an isocyanate group at the end are blocked. Blocked isocyanates blocked with agents are used. The blocked isocyanate A has an isocyanate group equivalent of 37.
0 (NCO content 11.35%), blocked isocyanate B has an isocyanate group equivalent of 900 (NCO content 4.67%), and blocked isocyanate C has an isocyanate equivalent of 1390 (NCO content 3.02%). Also, as a polyamide, active hydrogen (amino group)
Three kinds of polyamides having different equivalents, that is, a polyamide or a modified product thereof, which is a reaction product of a polybasic acid such as a dimer or trimer of an unsaturated fatty acid such as linoleic acid and a polyamine such as an aliphatic diamine, is used. ing.
Polyamide A has an active hydrogen equivalent of 350, polyamide B has an active hydrogen equivalent of 150, and polyamide C has an active hydrogen equivalent of 94.

The blocked isocyanate component and the polyamide component are blended in different amounts and in different combinations, but in each example, the isocyanate group (blocked with a blocking agent) contained in the blocked isocyanate component was used. But the isocyanate group after its dissociation)
The number of active hydrogens (amino groups) NA contained in the polyamide component is larger than the number NI of the above. That is, the number ratio NA / NI of these is
As shown in FIG. 2, 1.1 in the first embodiment and 1. in the second embodiment.
2, 1.5 in Example 3, 1.4 in Example 4, 1.5 in Example 5, 1.6 in Example 6, and 1. in Example 7.
5, 2.0 in Example 8, 2.0 in Example 9, 2.5 in Example 10, 3.2 in Example 11, and 5.0 in Example 12.

The numbers NI and NA are represented by "WI / isocyanate group equivalent of blocked isocyanate used", respectively, where WI (g) is the weight of the blocked isocyanate component and WA (g) is the weight of the polyamide component. , "WA / active hydrogen equivalent of polyamide used". Therefore, the number ratio NA / NI is "WA / WI
-Isocyanate group equivalent / active hydrogen equivalent.

In addition, the comparative examples are in accordance with the conventional general formulation, and as shown in FIG. 3, when the number ratio NA / NI is 1.0 or less, the blocked isocyanate component and It is blended with a polyamide component.

The vinyl chloride plastisol compositions of the respective examples and comparative examples comprising the above component materials were prepared by uniformly mixing the materials using a planetary mixer and then vacuum degassing and stirring for 60 minutes. I went by.

[Evaluation Test] Next, with respect to each plastisol composition of Examples 1 to 12 and Comparative Examples 1 to 11 prepared by the above-mentioned composition, an evaluation test was conducted on the adhesion of the coating film and the foaming property at the time of baking. .

<Adhesiveness> Regarding the adhesiveness of the coating film, in the case of the coating film formed by immediately applying and baking the prepared plastisol composition of each of Examples and Comparative Examples without leaving the composition (“sol”) "Immediately after preparation"), when the coating film thus formed is immersed in warm water for a long time ("after immersion in warm water"), and the prepared plastisol composition of each Example and Comparative Example An evaluation test was carried out for the case of a coating film formed by coating and baking after standing for a time (7 days) (“after leaving sol”). These tests are specifically as follows.

"Immediately after preparation of sol" ... A metal plate preliminarily subjected to cationic electrodeposition coating was used as a test piece, and the plastisol composition of each of the Examples and Comparative Examples prepared was substantially applied to the surface of the test piece. Width 20 x length 5 immediately without leaving
The coating was applied to 0 × thickness of 3 mm and then heated at 130 ° C. for 20 minutes for baking. Then, after leaving it to stand overnight at room temperature and allowing it to cool, a nail peeling test in which the coating film was peeled off with a nail was performed, and the adhesion to the electrodeposition coated surface was examined and evaluated from the peeled state of the coating film.

"After warm water immersion" ... Similarly to the above, the plastisol composition of each Example and Comparative Example was applied to a test piece and baked, and then the formed coating film was placed in warm water of 40 ° C. for 10 minutes.
Soaked for a day. Then, the same nail peeling test was performed on the coating film after the hot water immersion test, and the adhesion was evaluated.

"After leaving sol" ... The prepared plastisol composition of each of Examples and Comparative Examples was left in an atmosphere of 40 ° C for 7 days while being sealed in a container. Then, these compositions were applied to a test piece and baked in the same manner as above, and then a nail peeling test of the formed coating film was performed to evaluate the adhesion.

The evaluation criteria for adhesion are as follows. ○: Complete cohesive failure. Δ: Trace fracture in which interface fracture partially occurs. ▽: Trace destruction in which cohesive failure is partial. X: Complete interface destruction.

Here, cohesive failure means that the coating film of the plastisol composition adheres to the electrodeposition-coated surface and does not come off even if it is peeled off with a nail, and interface failure means that the coating film has a nail. When it is peeled off, it peels off from the interface with the electrodeposition coated surface. Therefore, the adhesiveness of the coating film is good in the case of cohesive failure and poor in the case of interface failure. The evaluation test results relating to the adhesiveness of this coating film are also shown in FIGS. 1 to 3.

<Foamability during baking> Regarding the foamability during baking, a metal plate coated with a cation type electrodeposition coating was used as a test piece in the same manner as in the case of the above-mentioned adhesion, and each surface was prepared. The plastisol compositions of the Examples and Comparative Examples were applied in a width of 20 × length of 50 × thickness of 5 mm and then in an oven 16
Baking was performed by heating at 0 ° C. for 90 minutes. It should be noted that this heating condition is assumed to be the maximum heating condition that the coating film of the plastisol composition after coating receives during baking and drying of the subsequent intermediate coating or top coating. Then, after allowing this to stand overnight at room temperature and allowing it to cool, the coating film was cut at a right angle to the surface, and the presence or absence of foaming inside the coating film was visually observed to evaluate the foaming property.

The evaluation criteria for the foamability of the coating film during baking are as follows:
It is as follows. ◯: No foaming (no abnormality) Δ: There is slight fine foaming. ▽: There are many fine bubbles. X: There is foaming. The results of the evaluation test of foamability during baking are shown in FIGS.
Are shown together with.

[Test Results] As shown in FIG. 3, Comparative Example 1 is a conventional general vinyl chloride-based plastisol composition,
The blocked isocyanate component and the polyamide component of the adhesion-imparting agent are blended at a ratio of NA / NI of 1.0, which shows that both the adhesiveness and the foamability during baking are good. . However, when paint fine powder is added to this, as in Comparative Examples 2 to 4, the adhesion of the coating film is reduced and foaming occurs in the coating film during baking. It can be seen that this tendency increases as the blending amount of the fine powder for paint meal increases. Further, this tendency is the same in Comparative Examples 5 to 11 in which the types of the blocked isocyanate component and the polyamide component are changed, and moreover,
It increases as the value of NA / NI decreases.

In contrast to these comparative examples, in Examples 1 to 12 in which the amount of the polyamide component was increased, good results were obtained with respect to the adhesion and foaming property of the coating film. For example, comparing Example 1 with Comparative Example 2, by increasing the content of the polyamide component and setting NA / NI to 1.1, the adhesiveness of the coating film after leaving the sol improved and the coating film Foaming is completely prevented. Then, from these results, the decrease in the adhesion of the coating film and the foaming of the coating film, which occur when the fine powder of the paint meal is blended, is the polyamide component in the adhesion-imparting agent composed of the blocked isocyanate component and the polyamide component. It can be easily prevented by blending the active hydrogen (amino group) number NA contained therein and the isocyanate group number NI contained in the blocked isocyanate component at a ratio NA / NI of 1.1 or more. .

Further, from the mutual comparison of the examples, it was found that the larger the value of the ratio NA / NI, the more preferable it is to prevent the foaming of the coating film, and it is more preferably 1.2 or more. It is preferably 1.5 or more, and most preferably 1.5 or more. However, the value of this ratio NA / NI is too large,
When the absolute amount of is excessive, as in Examples 10 and 11, the adhesiveness of the coating film after immersion in warm water tends to decrease. Therefore, it is understood that NA / NI is preferably 5.0 or less, more preferably 3.2 or less, and most preferably 2.5 or less. In Example 7, the adhesion after leaving the sol is slightly low, which is considered to be due to the small amount of the polyamide component compounded and the relatively small absolute amount of NA. Further, the reason why the adhesion after immersion in warm water in Example 9 is slightly low is considered to be because the absolute amount of NA is relatively large.

The vinyl chloride plastisol composition of the present invention was described as an example of an undercoat composition for an automobile body together with a comparative example. In the case of carrying out the present invention, this example is used. It is not limited, and the kinds and blending ratios of the components such as vinyl chloride resin, plasticizer, and filler can be variously changed. Further, it can be suitably applied not only as an undercoat composition but also as a sealing composition for steel plate joints or the like, or as a chipping resistant coating composition. Furthermore, these plastisol compositions can be advantageously applied not only to automobile bodies, but also to vehicles other than automobiles such as railways, home electric appliances, and the like.

[0062]

As described above, the vinyl chloride-based plastisol composition according to the present invention comprises a vinyl chloride-based resin and a plasticizer, a filler containing fine powder of paint meal, and an amino compound component containing active hydrogen. And a blocked isocyanate component in combination, the ratio of the number NA of active hydrogens contained in the amino compound component to the number Nl of isocyanate groups contained in the blocked isocyanate component NA / An essential component is an adhesion-imparting agent blended at a ratio of NI of 1.1 to 5.0.

Therefore, since the amino compound component containing active hydrogen of the adhesiveness-imparting agent and the blocked isocyanate component are blended at a ratio of NA / NI of 1.1 to 5.0, the amount of the paint residue is small. It is possible to prevent the foaming of the coating film and the decrease in the adhesiveness that occur when the powder is mixed. Therefore, the paint meal discharged in the painting process can be effectively reused, thereby contributing to the protection of resources and environment.

[Brief description of drawings]

FIG. 1 shows Examples 1 to 3 of the present invention and Comparative Examples 1 to 1.
4 is a table showing the composition of the vinyl chloride-based plastisol composition of No. 4 and the evaluation test results.

FIG. 2 is a table showing the composition of the main components of the vinyl chloride-based plastisol compositions of Examples 1 to 12 of the present invention and the evaluation test results.

FIG. 3 is a table showing the composition of the main components of the vinyl chloride-based plastisol compositions of Comparative Examples 1 to 11 and the evaluation test results.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Tamura 1141 Okawagahara, Iino, Fujioka-cho, Nishikamo-gun, Aichi 1 Aisin Kako Co., Ltd. (72) Toshihisa Ota 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd. (72) Inventor Mitsuo Nakajima 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd.

Claims (1)

[Claims] 1. An adhesiveness-imparting agent comprising a vinyl chloride resin and a plasticizer, a filler containing fine powder of paint meal, and a combination system of an amino compound component containing active hydrogen and a blocked isocyanate component. The ratio NA / NI of the number NA of active hydrogen contained in the amino compound component and the number NI of isocyanate group contained in the blocked isocyanate component is 1.1 to.
A vinyl chloride plastisol composition, which comprises, as an essential component, an adhesiveness-imparting agent blended in a ratio of 5.0.