JPS6049654B2 - Curable coating composition for polypropylene resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating used for the protection or cosmetic purposes of polypropylene resins, such as polypropylene homopolymers, ethylene propylene copolymers, ethylene propylene diene copolymers, etc., and more specifically relates to polypropylene resins. The present invention relates to a coating composition that satisfies adhesion with polypropylene resin, gasoline resistance, bending resistance, impact resistance, moisture resistance, water resistance, etc. when applied to sheets and molded articles.

Since polypropylene is nonpolar and crystalline, it has poor adhesion with ordinary paints and does not have adhesion performance that can withstand practical use.

In order to paint these objects, generally the non-polar surface of polypropylene is oxidized by chemical treatment, corona discharge, flame, ozone gas, etc., and then painted. It is not possible to uniformly treat objects to be coated that have the same properties, which poses a problem in the process. In addition, various primer compositions that have good adhesion to polypropylene have been proposed as methods for painting without these pretreatments.

According to Japanese Patent Publication No. 49-18081 and Japanese Patent Publication No. 49-5214, for example, compositions are made of cyclized rubber, aromatic petroleum resin, oil-soluble phenol resin, coumaron indene resin, ethylene vinyl acetate copolymer, and chlorinated polypropylene. .

These materials may have good adhesion to polypropylene but insufficient adhesion to the top coat, or may have good adhesion to both polypropylene and top coat but cannot be heated or cooled. It has the disadvantage of reduced adhesion after repeated cold and heat tests and water resistance tests.
The present inventors have already proposed an undercoat composition composed of chlorinated polypropylene and chlorinated ethylene-vinyl acetate copolymer which overcomes this drawback in Japanese Patent Application No. 106,618/1982. However, in recent years, painted objects used outdoors such as automobiles and motorcycles are required to have stronger adhesion, weather resistance, and gasoline resistance.

Regarding these, as seen in JP-A No. 52-98062, etc., there have been proposals that have a certain degree of gasoline resistance in cases where the painted surface is not scratched, but essentially the coating is based on crosslinking of chlorinated polypropylene. Since there is no fixation to the membrane, it is not fully satisfactory. The present inventors focused their studies on the fact that the chlorosulfone groups of chlorosulfonated ethylene-vinyl acetate copolymers and chlorosulfonated polypropylene or propylene copolymers can be crosslinked with amine curing agents, metal oxides, etc. As a result, a coating composition containing these as main components has excellent adhesion with polypropylene resin and ordinary topcoat paint, flex resistance, impact resistance, water resistance, and moisture resistance, as well as excellent gasoline resistance. The present inventors have discovered the following, and have completed the present invention.

Incidentally, it is known in JP-A-55-145775 that a chlorosulfonated ethylene vinyl acetate copolymer can be used as a printability improver for printing inks containing masticated polypropylene as the main active ingredient. , these are not intended to be cured.

In addition, chlorosulfonated polyethylene is used as a paint or adhesive material, but it itself does not adhere to polypropylene or propylene-based copolymers (Japanese Unexamined Patent Publication No. 52-13540, right column, lines 7 to 10). . H. of the ethylene vinyl acetate copolymer according to the present invention. The ridgeless sulfonated product is produced by preparing ethylene-vinyl acetate copolymer by a known method, for example, by dispersing or dissolving the raw material polymer resin in a solvent, and then adding sulfuryl chloride and chlorine at an appropriate temperature in the presence of a catalyst or under irradiation with ultraviolet rays. In the presence of gas or sulfur dioxide gas and chlorine gas. It can be obtained by matching.

In ethylene vinyl acetate copolymer, which is the raw material for chlorosulfonated ethylene vinyl acetate copolymer, if the vinyl acetate content is less than 5 mol%, the bending resistance at low temperatures, impact resistance, and adhesion with top coats will deteriorate. If the amount is more than 45 mol %, a tank remains in the coating film, and a coating hardness that can withstand practical use cannot be obtained. Furthermore, if the chlorine content is less than 5% by weight, the solubility in solvents will be poor, and if it is more than 50% by weight, it will have an adverse effect on various physical properties at low temperatures. If the sulfur content is less than 0.1% by weight, the crosslinking effect will be weak and gasoline resistance will not improve. Moreover, if it exceeds 5% by weight, the reaction rate with the curing agent is too fast and a sufficient pot life cannot be obtained. Further, the chlorosulfonated product of polypropylene or propylene-based polymer according to the present invention can be obtained by chlorosulfonation of polypropylene or a propylene-based copolymer by the above-described known method.

The chlorine content varies depending on the type of raw material, but for example, polypropylene can be used in the range of 10 to 50% by weight, and ethylene/propylene copolymer can be used in the range of 5 to 50% by weight. However, if the chlorine content is less than this, the solubility in solvents and the compatibility with other resins will deteriorate. This again. If it is more than that, the adhesion to polypropylene becomes worse. Sulfur content is 0-3. Ethylene acetic acid can be used within a range of 30% by weight, and if it is stored in, for example, a toluene solution, it may gel or the true adhesion to polypropylene may decrease.Ethylene acetic acid Chlorosulfonated vinyl copolymer (
Regarding the mixing ratio of polypropylene (hereinafter abbreviated as SCEVA) and chlorosulfonated product of polypropylene or a propylene copolymer (hereinafter abbreviated as SCPP), the true adhesion to polypropylene becomes better as the ratio of SCPP increases.

On the other hand, as the ratio of SCEVA increases, the true adhesion to polypropylene decreases, but the bending resistance and impact resistance at low temperatures of about -30'C are significantly improved, and the adhesion with ordinary top coats is also improved. increase Furthermore, the crosslinked product produced by the reaction between the chlorsulfone group and the curing agent exhibits very good gasoline resistance. However, an increase in the ratio of SCEVA impairs the true adhesion to polypropylene, leading to a decrease in gasoline resistance due to gasoline infiltration. Therefore, the blending ratio of both is 5 to 90 parts by weight of SCEVA to 95 to 1 part by weight of SCPP depending on the properties required by the application.
It may be advantageously selected within the range of the weight. In addition, when the sulfur content is zero, that is, chloride of polypropylene or propylene copolymer (hereinafter abbreviated as CPP) and SCEVA
In the case of a mixed system, CPP does not strongly crosslink with the curing agent, so the gasoline resistance is inferior to that of a composition of SCEVA and SCPP. For example, if a composition consisting of CPP (5SCEVA and a curing agent) is applied to a polypropylene board and a top coat is applied, the paint film is scratched and dipped in gasoline. After about 2 hours, the paint film will blister a little along the scratches. However, in the case of a composition consisting of SCPP.15SCEVA and a curing agent, no abnormality was observed even after 8 hours of immersion in gasoline.This result indicates that the composition of CPP, SCEVA, and curing agent is sufficient for practical use against mild gasoline contact. The curing agent used for crosslinking the chlorosulfonated product according to the present invention is a compound having two or more -NH2 groups or one -NH group in one molecule, such as ethylenediamine, Aliphatic amines such as diethylenetriamine, triethylenetetramine, pentaethylenehexamine, aminoethylethanolamine, methyliminobispropylamine, fats such as methanediamine, N-aminoethylpiperazine, isophoronediamine, 1,3-diaminocyclohexane Aromatic amines such as cyclic polyamines, m-xylylene diamine, and tetrachloro-p-xylylene diamine, polyamide resins obtained by reacting with polymerized fatty acids, and amine adducts obtained by cyanoethylating, hydroxyethylating, and epoxidizing amines. and amine-based hardeners such as modified amines having a heterocyclic structure. Known chlorsulfone group crosslinking systems such as metal oxides can be used alone or in combination.

To give a specific example of an amine curing agent, the amount of curing agent added can range from 1 to 10 equivalents to the chlorosulfone group of the chlorosulfonate, but preferably 1 to 4 equivalents. Furthermore, since excessive addition of amine may adversely affect moisture resistance and water resistance, an epoxy resin may be added as an amine scavenger. In addition, hydrochloric acid generated when a chlorosulfone group and an amine react is captured by the amine added in excess. Metal compounds such as , calcium stearate, lead stearate, calcium phthalate, zinc white, litharge, trilead-based lead sulfate, and epoxy compounds may be added. SCEVA used in the present invention. ．．
As the solvent for SCPP and CPP, ester solvents, ketone solvents, aromatic hydrocarbon solvents, etc. can be used, but toluene, xylene, etc. are preferable.

Furthermore, since it exhibits good dispersion with inorganic pigments such as titanium oxide and talc, these pigments can be used in combination as inorganic fillers.

The composition according to the present invention is applied to the surface of a sheet or molded article made of polypropylene resin, dried at room temperature, and then, if necessary, coated with a top coat and dried at room temperature or dried by heating.

Existing paints such as urethane paints, epoxy resin paints, alkyd resin paints, acrylic resin paints, etc. are suitable as the top coat paint used in this case. The resulting coating film had excellent gasoline resistance, moisture resistance, water resistance, chemical resistance, bending resistance, impact resistance, etc., and also showed strong adhesion to polypropylene resin. By using the paint of the present invention as an undercoat, a topcoat can be applied to a polypropylene resin in an inexpensive and simple manner without the conventional oxidation treatment, thereby imparting gasoline resistance, which has been considered difficult in the past. It became possible.

Furthermore, the composition of the present invention has considerable oil resistance depending on the formulation, so it can be used satisfactorily as a single-coat finishing paint in applications where only mild oil resistance is required. Next, the present invention will be specifically explained using Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 1 part by volume of a 20% toluene solution of SCPP (chlorine content (9)% by weight, sulfur content 0.0%) obtained by a known method using polypropylene as the raw material Two parts of a 20% toluene solution of SCEVA (chlorine content: 2% by volume, sulfur content: 0.2% by volume, vinyl acetate content: 28% by mole) obtained by the method were mixed to prepare a solution A.

Amine curing agent Epomate B-002 (trade name: manufactured by Ciel Chemical Co., Ltd., heterocyclic modified amine, amine value 327) 0
．． 45 parts by weight was dissolved in 30 parts by weight of toluene to obtain liquid B. Next, mix A and B at a weight ratio of 1:1 and apply the resulting composition to a polypropylene plate (2 x 50 x 80, wetting tension 34 dynes/Cm) whose surface has been cleaned with toluene to a thickness of 5 to 10 μm. I painted it with a brush to make it look like Narufu. After drying at room temperature for about 1 hour, apply a 2-component urethane paint to a thickness of 3 as the top coat.
Table 1 shows the performance of the coating film obtained by coating it to a thickness of 0 to 40μ and heating and drying it at 80°C for 3 minutes. Example 2 15 parts by weight of a 20% toluene solution of SCPP (chlorine content 30% by weight, sulfur content 0.9% by weight) whose base material is polypropylene, SCEVA (chlorine content 20% by weight,
Sulfur content 0. Heel weight%, vinyl acetate content 28 mol%)
15 parts by weight of a 20% toluene solution were mixed to prepare a liquid A.

0.45 parts by weight of Epomate B-002 was dissolved in 30 parts by weight of toluene to obtain liquid B. Next, a composition obtained by mixing liquids A and B at a weight ratio of 1:1 was coated in the same manner as in Example 1, and the performance of the resulting coating film is shown in Table 1. Example 3 A 20% toluene solution w parts by weight of SCPP (chlorine content 30% by weight, sulfur content 1.0% by weight) whose base material is polypropylene, SCEVA (chlorine content 20% by weight, sulfur content 0J) 2 parts by volume of a 20% toluene solution containing vinyl acetate (by weight %, vinyl acetate content 28 mol%), epoxy resin Epicoat 828 (trade name: manufactured by Ciel Chemical Co., Ltd., epoxy equivalent weight 184 ~
194) 1 part by weight was mixed to prepare liquid A.

0.9 parts by weight of Epomate B-002 was dissolved in toluene to prepare B liquid. Next, a composition obtained by mixing liquid A and liquid B at a weight ratio of 1:1 was applied in the same manner as in Example 1, and the performance of the resulting coating film is shown in Table 1. Example 4 Chlorinated polypropylene Superchron 8031. (Product name: Sanyo Kokusaku Valve Co., Ltd., chlorine content 26% by weight) No. 2
0% toluene solution 10 parts by weight SCEVA (chlorine content 2
0 wt%, sulfur content 0.9 wt%, vinyl acetate content 28 mol%).
It was made into a liquid.

0.45 parts by weight of Epomate B-002 was dissolved in 30 parts by weight of toluene to obtain liquid B. Next, a composition obtained by mixing liquids A and B in a weight ratio of 1:1 was coated in the same manner as in Example 1, and the performance of the resulting coating film is shown in Table 1. Example 5 SCPP (chlorine content: 2% by weight, sulfur content: 1.0% by weight) made from polypropylene 20% toluene solution 1
5 parts by weight, 20% of SCEVA (chlorine content 20% by weight, sulfur content 3% by weight, vinyl acetate content 28% by mole)
15 parts by weight of the toluene solution were mixed to prepare A liquid 4.

2.3 parts by weight of a polyamide resin curing agent Gutdomide G-700 (trade name; manufactured by Tobu Kasei Co., Ltd., polyethylene polyamine-polymerized fatty acid condensate, amine value 95) was dissolved in 30 parts by weight of toluene to obtain liquid B. Next, a composition obtained by mixing liquids A and B in a weight ratio of 1:1 was coated in the same manner as in Example 1, and the performance of the resulting coating film is shown in Table 1. Example 6 50 parts by weight of a 20% toluene solution of SCPP (chlorine content 3% by weight, sulfur content 0.6% by weight) made of polypropylene as raw material, SCEVA (chlorine content 20% by weight, sulfur content 0.6% by weight). Heel weight%, vinyl acetate content 28 mol%)
10 parts by weight of 0% toluene solution, 11.5 parts by weight of titanium oxide, 1.0 parts by weight of talc. Saliva part, tribasic lead sulfate 0.5 part by weight, carbon black 0. After mixing the parts and dispersing the pigment in a sand mill, 2 parts of Epomate B-0.02 was added to 2 parts of toluene. Add the curing agent in which the weighing part has been dissolved, mix thoroughly, and use toluene to obtain a NO. The composition obtained by adjusting the viscosity so that the viscosity was adjusted to 16 seconds with a food cup of No. 4 was sprayed onto the polypropylene plate shown in Example 1 to a thickness of 5 to 10 .mu.m.

After drying to the touch, a 2-component urethane paint was spray-painted to a film thickness of 30 to 40 μm, and the performance of the 3-powder and heat-dried film at 80° C. is shown in Table 1. Comparative Example 1 Three parts of a 20% toluene solution of SCPP (chlorine content: 2% by weight, sulfur content: 1.0% by weight) made from polypropylene was added to A.
It was made into a liquid.

Gutdomide G-7002. The weighed portion was dissolved in 30 parts by weight of toluene to obtain liquid B. Next, mix A and B in a weight ratio of 1
Table 1 shows the performance of the coating film obtained by coating the composition obtained by mixing 1:1 with the same method as in Example 1. Comparative Example 2 Three parts of a 20% toluene solution of SCEVA (chlorine content: 2 volume %, sulfur content: 0.9 weight %, vinyl acetate content: 28 mol %) was used as liquid A.

0.45 parts by weight of Epomate B-002 was dissolved in 3 parts by volume of toluene to prepare B solution. Next, mix A and B in a weight ratio of 1
Table 1 shows the performance of the coating film obtained by coating the composition obtained by mixing 1:1 in the same manner as in Example 1. Comparative Example 3 Chlorinated polypropylene Super Chron 803MW (trade name; manufactured by Sanyo Kokusaku Valve Co., Ltd., chlorine content 29.5% by weight)
20% toluene solution w parts by weight, chlorinated ethylene vinyl acetate Superclone BX (trade name; manufactured by Sanyo Kokusaku Valve Co., Ltd., chlorine content 1% by weight, vinyl acetate content 28 mol%)
Table 1 shows the performance of the coating film obtained by mixing 20 parts by weight of a 20% toluene solution of We made 100 5-diagonal squares that reached the base material, covered them with cellophane tape, and then peeled them off in a 180-degree direction to determine the number of remaining squares.

Gasoline resistance: Scratches reaching the substrate are made on the painted surface (x mark), and regular gas resistance is applied at 20'C. The condition of the coating film was examined by immersing it in phosphorus.

Water resistance: The condition of the coating film was examined by immersing it in hot water at 50°C for 120 hours.

Humidity resistance: 12 to 50°C and relative humidity of 98% or more
The condition of the coating film was examined after being left for 0 hours.

Flexibility: After being left in an atmosphere of -30°C for 3 hours, it was taken out and immediately bent 180 degrees with a 112φ inch mandrel to examine the state of the coating film.

Impact resistance: After being left in an atmosphere of -30'C for 3 hours, it was taken out and immediately subjected to an impact test using a DuPont type impact tester to examine the condition of the coating film.

Claims (1)

[Claims] 1 Chlorsulfonation with a sulfur content of 0.1 to 5.0% by weight and a chlorine content of 5 to 50% by weight obtained by chlorosulfonation of an ethylene vinyl acetate copolymer with a vinyl acetate content of 5 to 45 mol% Ethylene vinyl acetate copolymer (A),
Chlor or chlorosulfonated product (B) of polypropylene or propylene copolymer having a chlorine content of 10 to 50% by weight and a sulfur content of 0 to 3.0% by weight, and a group capable of crosslinking with the chlorsulfone group. A curable coating composition for polypropylene resin, comprising a mixture of two or more substances (C) as a main binder element.