JPS6312651A - Resin dispersion and production thereof - Google Patents

Abstract

PURPOSE:A dispersion, obtained by dispersing a specific modified polypropylene in a solid state in a hydrocarbon solvent, capable of being an uniform dispersion simply by lightly stirring even after allowing to stand without swelling, dissolving or flocculating of dispersion particles and causing clogging of nozzles as well as surface unevennesses in coating. CONSTITUTION:A resin dispersion, obtained by dispersing a modified polypropylene graft modified with an unsaturated carboxylic acid (anhydride) in a solid state in a hydrocarbon based solvent, capable of giving powder of the modified polypropylene, prepared by evaporating the above-mentioned dispersion to dryness at ordinary temperature and having >=70% crystallinity measured by an X-ray diffractometry, 0.3-1.5dl/g intrinsic viscosity and 0.1-10wt% content of the unsaturated carboxylic acid (anhydride). In cooling a solution prepared by dissolving the above-mentioned modified polypropylene (provided that only the crystallinity is >=50%) in the hydrocarbon based solvent to give the aimed resin dispersion, the cooling rate at 90-70 deg.C is 1-20 deg.C/hr to afford the dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin dispersion that can be used in many applications such as paints and adhesives, and a method for producing the same.

[Conventional technology]

A technique is already known in which a modified polyolefin such as polypropylene is graft-modified with maleic anhydride and the like is dispersed in a solid state in an organic solvent and used for paints and the like. If similar techniques are included, for example, JP-A-51-150534, JP-A-52-5848, JP-A-52-
30639, 52-63227, 57-12072
, 57-209961, 58-118240, 5
Publications No. 8-173173, Special Publication No. 1227/1973
0, 45-10630, 46-15015, 47
-24935, 48-29301, 51-1824
1, No. 55-44110, No. 59-16574, and Japanese Utility Model Publication No. 61-3636, various dispersion methods and applications have been proposed.

[Problem that the invention seeks to solve]

Among the dispersion methods according to the above-mentioned prior art, a typical method involves mechanically pulverizing modified polyolefin and then swelling it in a solvent.
Dispersion method: The modified polyolefin is precipitated and dispersed by dissolving the modified polyolefin in a solvent at a high temperature, cooling the solution, pouring a cold solvent into the solution, or pouring the solution into a cold solvent. There is a way. However, in either case, the dispersed particles tend to swell or dissolve in the solvent, so the particles tend to aggregate with each other, resulting in lumps. Further, sediments generated during storage of the dispersion may not be easily dispersed by stirring. This lack of stability of the dispersion not only causes storage problems, but also causes problems such as unevenness on the painted surface when the dispersion is used.
This can also cause troubles such as clogging of the nozzle of the coating machine.In order to solve these problems, the above-mentioned publication describes the use of a dispersing solvent as a mixture of a polar solvent and a non-polar solvent. However, this method has drawbacks such as complicated preparation and recovery of the solvent, and a solution that does not require the use of such mixed solvents has been desired.

[Means for solving problems]

In view of the above problems, the present inventors conducted various studies and found that 1. It was discovered that the problems could be solved by using specific raw materials and dispersing them by a specific method, and the present invention was completed.

That is, the present invention provides a resin dispersion in which a modified polypropylene partially or wholly graft-modified with an unsaturated carboxylic acid or its anhydride is dispersed in a hydrocarbon solvent in a solid state, the dispersion being heated at room temperature. A resin dispersion in which modified polypropylene powder obtained by evaporation to dryness has the following properties (a) to fc).

Crystallinity measured by X19 diffraction method is 70%
That's all.

(b) ffi limiting viscosity'iff, (7?) Ka0.3
It is in the range of 1.5 cig/g.

(y) The content of unsaturated carboxylic acid or its anhydride is 0.
Chill in the range of 1 to 10% by weight. '' is the first invention, and ``a modified polypropylene partially or wholly graft-modified with an unsaturated carboxylic acid or its anhydride has a crystallinity of 50% or more as measured by X-ray diffraction method; Heating an unsaturated carboxylic acid or its anhydride having a grafting amount in the range of 0.1 to 10% by weight and an intrinsic viscosity (1) in the range of 0.3 to 1.5 (IIl/F!) In the method of producing a resin dispersion by dissolving 9 in a hydrocarbon solvent and cooling the resulting solution,
A method for producing a resin dispersion in which the cooling rate is in the range of 1 to 20°C/hour in the temperature range of 0 to 70°C. ' is the second invention.

[Modified polypropylene]

The modified polypropylene used in the present invention is polypropylene partially or entirely grafted with an unsaturated carboxylic acid or its anhydride. The raw material polypropylene is not only a homopolymer of propylene, but also propylene and other α-olefins such as ethylene, 1-butene, imbutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3”-mef-1-pentene, 2-methyl-1-pentene, 1-
As long as the conditions described below are satisfied, about 5% by weight of hepte/etc. may be copolymerized.

Examples of unsaturated carboxylic acids or anhydrides thereof to be grafted include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, allyl-succinic acid, mesaconic acid, and glutaconic acid. ,
Unsaturated dicarboxylic acids such as nadic acid, methyl nadic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, allylsuccinic anhydride, glutaconic anhydride, nadic anhydride, methyl anhydride Examples include unsaturated dicarboxylic anhydrides such as nadic acid, tetrahydrophthalic anhydride, and methyltetrahydrophthalic anhydride, and a mixture of two or more of these components may be grafted simultaneously.

Among these unsaturated carboxylic acids or acid anhydrides, maleic acid, maleic anhydride, nadic acid, or nadic anhydride is preferably used.

A well-known method can be used as the grafting method. For example, the above-mentioned polypropylene and the above-mentioned unsaturated carboxylic acid are heated to a high temperature in the presence or absence of a solvent, with or without the addition of a radical initiator.

The properties of the modified polypropylene were determined by X-ray diffraction method (the modified polypropylene was hot pressed at 200'0.50 kg/cJ for 5 minutes, and then cold pressed at 5 [1 to 9/- for 5 minutes). The degree of crystallinity measured using a 1-thick sheet is 50% or more, preferably 55% or more, and the amount of grafting of unsaturated carboxylic acid, etc. is 0.1 to 10% by weight, preferably 0.3 to 6ffiffi%. and the intrinsic viscosity [η] in decalin at 135°C is in the range of 0.3 to 1.5 dl/El %, preferably 0.5 to 1.2 d (1/fl). Even if a crystallization degree lower than 50% is used, it is difficult to increase the crystallinity of the dispersed particles described below to 70% or more.Furthermore, if the grafting amount is less than 0.1% by weight, the adhesion to metals will be poor. On the other hand, if it exceeds 10% by weight, the adhesion to polyolefins becomes poor.

If the intrinsic viscosity [η] is less than 0.3, the cohesive force of the modified polypropylene will be insufficient, resulting in a lack of adhesive strength, while if it exceeds 1.5 dβ/g, the fluidity during melting will be lacking. It becomes difficult to obtain a smooth coating film or adhesive layer.

[Resin dispersion]

The resin dispersion of the present invention is obtained by dispersing the modified polypropylene in a solid state in a hydrocarbon solvent.

The hydrocarbon solvent is one that can dissolve modified polypropylene at high temperatures and does not substantially dissolve at room temperature.
Examples include aromatic hydrocarbons such as toluene and xylene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and aliphatic hydrocarbons such as hexane, heptane, decane and mineral spirit. Although the present invention was completed to solve the above-mentioned problems, a chlorinated hydrocarbon solvent or a polar solvent may be mixed and used within a range that does not impede the effects of the present invention.

The modified polypropylene particles in the dispersed state are generally and preferably spherical, but need not necessarily be spherical. The average particle size of the particles is usually 1 to 20μ, preferably 5 to 15μ. The concentration of modified polypropylene particles (solid content concentration) in the dispersion is usually 5 to 40% by weight.

When the resin dispersion of the present invention is evaporated to dryness at room temperature, a modified polypropylene particle powder is obtained. The degree of crystallinity of the powder measured by X-ray diffraction without applying heat is required to be 70% or more, preferably in the range of 75 to 85%.

If the crystallinity is less than 70%, the particles tend to swell or dissolve in a hydrocarbon solvent, and as a result, the particles tend to aggregate. In addition, the intrinsic viscosity [ma] of the particles and the content of unsaturated carboxylic acids, etc. in the modified polypropylene constituting the particles must be within the ranges described in the [modified polypropylene] section above, and the reason is This is the same as described in that section.

Note that the resin dispersion of the present invention may contain υ, which does not contradict the purpose.
Pigments, fillers, stabilizers and other additives may also be included.

[Invention of manufacturing method for resin dispersion]

To produce the resin dispersion of the present invention, the above-mentioned modified polypropylene is usually mixed with a hydrocarbon solvent so that the concentration of solids in the dispersion falls within the above-mentioned range, and is completely dissolved by heating. let The temperature during melting is usually 120 to 150°C. The solution is then cooled to precipitate the modified polypropylene, but it is necessary to adjust the average cooling rate in the temperature range from 70 to 90°C to 1 to 20°C/hour, preferably from K to 10°C/hour.

In this case, it is preferable that the mixture be cooled while stirring, and that the cooling rate be uniform within the same temperature range. If the cooling rate is faster than the upper limit, the crystallinity of the particles will be lower than the lower limit, and if it is slower than the lower limit, it is not preferable in terms of production efficiency. Note that the temperature range in which the cooling rate needs to be controlled is 90 to 70°C, but 150 to 90°C
It is also preferable to control the temperature in the same manner at 7o to 30°C.

〔Effect of the invention〕

In the resin dispersion of the present invention, there is almost no swelling or dissolution of the dispersed particles, so even if the particles do not aggregate and settle when left standing, they can be easily made into a uniform dispersion by stirring lightly. be able to. Therefore, even when used as a paint, coating material, or adhesive, problems such as clogging of the nozzle of a coating machine can be suppressed, and there is almost no unevenness on the painted surface. Furthermore, when the resin dispersion of the present invention is used in adhesives between metals or between metals and polyolefins, heat sealants, coating materials for metals, paints, etc.
Excellent adhesive strength, heat seal strength, and coating film properties.

The present invention will be explained in detail below.

〔Example〕

Example 1 Contains 0.5% by weight of maleic anhydride, [η] is 1 dI
//l of maleic anhydride grafted PP at 200'C.

9/cr for 50! Heat press for 5 minutes and then press for another 50 kg/
A sheet with a thickness of 1 mm was prepared by cold pressing at d for 5 minutes, and the crystallinity of the sheet was measured by xa diffraction method and found to be 57%.

15 parts by weight of the modified PP and 85 parts by weight of toluene were placed in an autoclave equipped with a stirrer, heated to 140°C to completely dissolve the resin, and then cooled to 90°C at a cooling rate of 25°C/hour while stirring. , and was gradually cooled to 70° C. at a cooling rate of 5° C./hour. Subsequently, the temperature was lowered to 30°C at a cooling rate of 40°C/hour, and a milky white uniform dispersion was obtained.

The average particle size of the dispersed particles of the dispersion was measured using a coulter counter and found to be 7 microns.

The dispersion was filtered through a 100-mesh SUS Stascreen filter, the filter residue was dried, and its weight was measured. The P residue was 0.1 parts by weight or less based on 100 parts by weight of the dispersion.

The polymer powder obtained after drying the dispersion under reduced pressure at room temperature for 24 hours was filled in a glass holder, and its crystallinity was measured by x-ray diffraction and found to be 79%.

The dispersion was applied to aluminum foil using a bar coater, air-dried, and then heated for 20 seconds in an air open set at 170° C., resulting in a coated foil with a uniform and transparent coating. That is, the film appearance was uniform. This coated foil and PP sheet (Higashishanaguchi Kagakusha Φ200T-T)
to 180℃ using a method compliant with J Engineering S Z17Q7.
After thermal bonding was carried out by applying a pressure of 1 kg/d for 2 seconds, the peel strength (180 degree peeling) at room temperature was measured and found to be 2.5 kg/15 mm. Also, the peeled surface is the basket side/P.
The dispersion, which had a good appearance with no lint on the P side, was taken into a bridge measuring cylinder and left to stand at room temperature for 3 months.The dispersed particles had completely settled, but the cylinder A homogeneous dispersion was restored by hand shaking for 1 minute. When the recovered dispersion was filtered through a 100-mesh filter and the amount remaining after filtration was measured, it was found that the dispersion was 100%
It was found that the amount was 0.1 part by weight or less, and the redispersibility was good.

Examples 2 to 6 and Comparative Examples 1 to 6 Dispersions were prepared by changing various conditions in Example 1,
Its performance was investigated in the same manner as in Example 1.

Claims (2)

[Claims] (1) A resin dispersion in which modified polypropylene partially or wholly graft-modified with an unsaturated carboxylic acid or its anhydride is dispersed in a hydrocarbon solvent in a solid state, and the dispersion is evaporated at room temperature. A resin dispersion in which modified polypropylene powder obtained by drying has the following properties (a) to (c). (a) The degree of crystallinity measured by X-ray diffraction is 70% or more. (b) The intrinsic viscosity [η] is in the range of 0.3 to 1.5 dl/g. (c) Content of unsaturated carboxylic acid or its anhydride is 0
．． It ranges from 1 to 10% by weight. (2) Modified polypropylene partially or entirely graft-modified with an unsaturated carboxylic acid or its anhydride, the degree of crystallinity measured by X-ray diffraction is 50% or more, and the unsaturated carboxylic acid Or, the amount of grafted anhydride is in the range of 0.1 to 10% by weight, and the intrinsic viscosity [η] is in the range of 0.3 to 1.5 dl/g, in a hydrocarbon solvent under heating. In a method for producing a resin dispersion by dissolving and cooling the resulting solution,
The cooling rate is 1 to 2 in the temperature range of 1 to 70°C.
A method for producing a resin dispersion in the range of 0°C/hour.