JPH03199274A - Chlorinated polyolefin coating composition - Google Patents

Abstract

PURPOSE:To provide the title composition of high weatherability, containing a solvent-soluble chlorinated polyolefin produced by suspending pulverized polyolefin powder in an aqueous medium followed by chlorination. CONSTITUTION:The objective composition containing a chlorinated polyolefin produced by suspending pulverized polyolefin powder with a specific surface area of 300-20000cm<2>/g in an aqueous medium followed by chlorination. It is preferable that until completion of the chlorination, the disintegration treatment along with grinding treatment of the polyolefin granules under chlorination be made either repeatedly at least once or continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a coating composition with good weather resistance using a chlorinated polyolefin produced by a water-based method.

[Conventional technology]

Chlorinated polyolefins produced by a water-based method are used for molded products and resin modifiers due to their characteristics due to non-uniformity of chlorination compared to solvent-based chlorinated products.

However, it is not possible to make a homogeneous solution of conventional water-based chlorinated polyolefins in commonly used inexpensive solvents (e.g. toluene, xylene), and a method of dissolving them by heating has been proposed (Japanese Patent Application Laid-Open No. 1983-1989-1). 153853), All
'j It's not something I can do. Therefore, it is difficult to use it for paints.

On the other hand, when chlorinated in a conventional chlorine-resistant solvent, the molecular weight range is narrow due to a homogeneous reaction, resulting in a resin that forms a hard wave film.When used as a paint binder, η 40 to 45 parts is always required, and therefore has the drawback of poor weather resistance and deterioration of the coating film over time.

[Problem to be solved by the invention]

Fugenon et al. conducted extensive research to develop a weather-resistant resin for coating film 1 that does not require large amounts of plasticizer, and found that if chlorinated under conditions that make it soluble in solvents in an aqueous medium, it can be used as a powder. The surface of the body resin is chlorinated to form a heterogeneous reactant, and the degree of chlorination can vary widely. At the same time, the molecular weight range is widened, making it possible to obtain a flexible chlorinated resin. This discovery led to the present invention.

As a result, when used as a paint binder, the amount of additives added can be greatly reduced, and a coating film with good weather resistance is naturally obtained, with less deterioration of the coating film caused by plasticizers.

[Means and actions to solve the problem]

As separately requested by the sender, the method of aqueous chlorination suitable for solvent-soluble and weather-resistant paints is as follows: 1. Micronization to a specific surface area of 300 to 20,000 cnf/g. Conducting a reaction using the prepared polyolefin powder, 2
, Until the chlorination reaches the degree of chlorination corresponding to the lowest value of the heat softening temperature of the chlorinated polyolefin, the reaction temperature is adjusted to below the lowest value of the heat softening temperature. 3. The degree of chlorination is adjusted to 50%. 4. Before the end of chlorination, the polyolefin particles being chlorinated are simultaneously disintegrated and pulverized.

By these means, the heterogeneously chlorinated product becomes solvent soluble and at the same time provides a weather resistant coating composition with a small amount of plasticizer.

In other words, by increasing the surface area through appropriate pulverization and adjusting the chlorination temperature at the initial stage of the reaction, heterogeneous chlorination can be achieved at a moderate level that achieves both solvent solubility and a wide chlorination degree distribution that provides weather resistance. Become.

Further details of the structure of the present invention are as follows.

■, grinding degree, specific surface area: 300-20.1100C
iI/g is appropriate, and if it exceeds 20.000 car/g, workability will decrease. 2. The thermal softening temperature of polyolefins decreases due to chlorination, reaching the lowest level at a certain average degree of chlorination, and further increases in chlorination. The thermal softening temperature is indicated by the inflection point of the DSC endothermic curve as shown in Figure 19 and Figure 2.

3. Polyethylene or polypropylene is used as the polyolefin. 4. Disintegration and pulverization during chlorination is carried out one or more times in Sochi or continuously using a wet method 1. Impact using a mechanical crusher such as a ball mill, homogenizer, or centrifugal pump. 5. It is difficult to achieve solvent solubility unless the degree of chlorination is 50% or higher. [Examples] The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. It's not something you can do.

Example 1 500 g of resin (PE with an Ml value of 20) and 81 g of water were placed in a 101 separable flask equipped with a stirrer, UV irradiation device, and reflux condenser. A slurry was prepared using a small amount of a surfactant T'l agent, heated to 50° C., and chlorine gas was introduced at a rate of 500 g/I (while irradiating with UV light).

The reaction temperature was maintained at 50 °C until the estimated degree of chlorination was 35%, which corresponds to the lowest temperature point on the thermal softening curve in Figure 2;
The temperature was raised to 90°C at a heating rate of about 20°C/H, and the temperature was maintained to obtain a chlorinated product of 65% or more.

Example 2 PP with an average molecular weight of 4000 was produced using the apparatus and method of Example 1.
It was used. According to FIG. 2, the chlorination reaction initiation temperature was set at 70°C.

Example 3 A stirrer, a reflux condenser, and a UVN were placed in a separable flask with a specific surface area of 6,600 cnf/g (7).
)PE (Ml(i+'(1,5) 500g+,-
Add Shokuma surfactant +1 agent and 8g of water, heat, stir, and UV.
Chlorine was introduced while irradiating the reactor, and the reaction solution was forcedly circulated using a centrifugal pump without interrupting the reaction to disintegrate the aggregates generated during the reaction. The degree of chlorination obtained was 66.8%
Met.

Example 4 Stirrer, reflux condenser, UVII (10/separable flask with injection device, specific surface area 200c
rl/g of PP was dissolved in a solvent and precipitated with a non-solvent, then ground in a ball mill to obtain a specific surface area of 5,900 cn.
f/g PP. A small amount of surfactant fl[agent and 81 g of water were added to 500 g of this PP, and chlorine was introduced while heating and stirring and UV irradiation. At a degree of chlorination of about 40%, the reaction solution was taken out, washed with water, pulverized in a ball mill, charged into a flask again, and chlorinated until the degree of chlorination reached 67.0%.

Comparative Example I 100 g of polyethylene of M120 was dissolved in 5 V, Z tetranomial hydrogenated carbon, and after being sufficiently dissolved at 85° C., chlorination was performed while irradiating with light. When the chlorine content reached 167% by weight, the chlorination reaction was stopped, residual chlorine was removed, and a white powder was collected by steam distillation.

Comparative Example 2 Polypropylene with a molecular ff of 14,000 was dissolved in 1 of quaternary hydrogenated carbon at 105°C under an IF effort of 2 kg/LOi.
After sufficient dissolution, chlorination was performed while irradiating with light. When the chlorine content reached 65% by weight, the chlorination reaction was stopped, residual chlorine was removed, and white powder was extracted by steam distillation.

Regarding the samples obtained in Examples 1 to 4 and Comparative Examples 1 to 2, the average molecular weight, molecular weight dispersity, and each test! '1 of 20
% toluene solution polishing mild steel plate (SPCCll33!4
1 Cold rolling B, 0.8X50X 150m/m
) and after air drying day and night, the pencil hardness.

Table 1 shows the results of bending resistance and impact resistance tests. In addition, a white top coat paint was prepared using each sample. Weather resistance as mentioned above is an essential condition for paints, but U
VI! Changes in whiteness due to Q radiation were tracked, and changes in the coating film were also observed.

The composition of the paint and the waveforms used to prepare the test pieces are as follows.

Paint composition resin 20.0 parts by weight Plasticizer (Toyobarakku A-40) 4.0 Titanium dioxide (
R-820) 25.0 Stabilizer (Epicote 8
2g) 0.5 thixotropic agent (bentone 34) 1.5 xylene 49.0 total
100.0 A test piece was prepared by kneading the paint having the above composition in a sand mill, undercoating Epozinc on a sandblast board, and painting the undercoat with a brush. After the test plate was air-dried for 7 days, a HW mercury lamp was applied to the test piece attached to the rotating drum for 30 minutes.
It was irradiated from a distance of 1.5 cm and changes in whiteness and coating surface were tracked at predetermined intervals.

The performance of the coating film is shown in Table 11 and Table 2.

Table-1 Note 1) Average molecule ff1 = G with polystyrene as standard,
Measured values by P, C,.

Note 2) Dispersity/Mw/Mn My...Weight average molecule a Mn...Number average molecular area Note 3) Flexibility: 17
The condition of the coating film was examined by bending it 180' using a 2φ inch mandrel.

Note 4) Impact resistance: Strike core 1/2φ using DuPont impact tester
inch, load 500g, 50cm for surface striking
In the case of back RR, it was dropped from 25 cm.

Table 2 Relationship between UV irradiation time and coating film deterioration (weather resistance) By incorporating an olefin, a coating material with excellent weather resistance was obtained and the present invention was completed.

[Brief explanation of drawings]

FIG. 1 is a DSC endothermic curve in an example of the present invention, which is a diagram showing the relationship between the amount of heat absorbed and the temperature, and FIG. 2 is a diagram showing the relationship between the temperature and the degree of chlorination. As shown in Table 1, by using the composition of the present invention, a coating composition with an excellent surface can be obtained. Also, as is clear from Table 2, the comparison sample obtained by the conventional method had a P! I! Although the film was significantly deteriorated and its weather resistance was poor, the paint using the composition of the present invention hardly required a plasticizer and formed a film with excellent weather resistance. [Effects of the Invention] As shown in the above examples, water-based chlorinated polyurethane that is solvent soluble and exhibits moderate heterogeneity (ii) Figure 1 procedural amendment (voluntary) Figure 2 1, Description of the case 1999 Patent Application No. 344659 2 Title of the invention Chlorinated polyolefin coating composition 3゜Relationship with the case Patent applicant Address 4-5 Marunouchi-chome, Chiyoda-ku, Tokyo given name
Name (234) Sanyo Kokusaku Pulp Co., Ltd. 4, Agent Address: 16-5 Kitajomono-cho, Kami 01, Chiyoda-ku, Tokyo, Subject to Correction Chlorination Degree (W%) Page 7, line 17 of the specification states, “Dissolved in solvent” and corrected it to "J by dissolving it in a solvent and using a poor solvent".
1. Sorry,

Claims (5)

[Claims] (1) Specific surface area is 300cm^2/g ~ 20,000c
A coating composition with good weather resistance containing a solvent-soluble chlorinated polyolefin obtained by suspending a polyolefin powder finely divided into m^2/g in an aqueous medium and chlorinating it. (2) The weather-resistant material containing the solvent-soluble chlorinated polyfin according to claim 1, wherein the polyolefin particles undergoing the chlorination reaction are subjected to disintegration and pulverization treatment repeatedly or continuously one or more times until the chlorination is completed. Good paint composition. (3) Until the chlorination reaches a degree of chlorination corresponding to the lowest thermal softening temperature of the chlorinated polyolefin, the reaction temperature is kept at or below the lowest thermal softening temperature of the chlorinated polyolefin.
A coating composition with good weather resistance containing the solvent-soluble chlorinated polyolefin described above. (4) A coating composition with good weather resistance, containing the solvent-soluble chlorinated polyolefin according to any one of claims 1 to 3, which has a degree of chlorination of 50% by weight or more. (5) A coating composition with good weather resistance containing the solvent-soluble chlorinated polyfin according to any one of claims 1 to 4, wherein the polyolefin is polyethylene or polypropylene.