JP3059766B2 - Modified propylene polymer dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a modified propylene polymer dispersion. More specifically, heat sealants for metal foil for medical or food packaging and propylene polymer molded products, adhesion promoters for industrial metal products and propylene polymer, or hot stamping on propylene polymer molded products The present invention relates to a modified propylene polymer dispersion useful as a heat sealant, and further, as an anticorrosive and adhesive agent for metal cans.

[0002]

2. Description of the Related Art Dispersions containing a propylene polymer modified by adding maleic anhydride to a propylene polymer are:
Internal coating composition for can making (JP-B-55-44110), a resin dispersion that can be used for paints, adhesives, etc.
No. 1) and the like. Further, a composition with an organic solvent containing an unsaturated carboxylic acid ester of a low-molecular-weight polyolefin as a component (JP-A-1-175436,
JP-A-1-74537) is also known as a surface treatment agent. Furthermore, propylene, ethylene and carbon atoms of 4
Modified polymers obtained by graft copolymerizing an unsaturated carboxylic acid or a derivative thereof with an olefin copolymer of α-20 and α-20 are also disclosed in JP-A-2-6513.

[0003]

[Problems to be solved by the invention]
The resin dispersions disclosed in 55-44110 and JP-A-63-12651 tend to change in viscosity during storage, and therefore, these resin dispersions are controlled to a desired film thickness.
It is difficult to apply it to molded products and the like. Furthermore, if the concentration of the resin in these dispersions is increased to reduce the volatile components, the viscosity increases and it becomes impossible to apply uniformly, or in extreme cases, gelation occurs and the fluidity is lost. There is also. The present invention solves the conventional problems as described above, and provides a propylene polymer dispersion having little change over time in viscosity during storage and also having a low viscosity and good workability even at a high solid content. The purpose is to do so.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have solved the above-mentioned problems. That is, the present invention provides a method for carbonizing a modified propylene polymer particle in which at least a part of maleic anhydride in a propylene polymer modified with maleic anhydride is esterified and having an average particle size of 0.1 to 10 μm. It is intended to provide a modified propylene polymer dispersion liquid dispersed in a hydrogen-based medium.

Hereinafter, the present invention will be described in more detail.
The propylene polymer as a raw material of the modified propylene polymer that can be used in the present invention has a propylene content of 55%.
It is not particularly limited as long as it is at least% by weight,
For example, propylene homopolymer / propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / 1-hexene copolymer, propylene / ethylene / 1-
Butene terpolymers and the like can be mentioned. These propylene polymers or copolymers are JIS K721
The melt flow rate measured at 230 ° C. and a load of 2.16 kg based on the temperature 0 is 0.3 g / 10 min or more, preferably 0.5 g / min.
５０50 g / 10 min is suitable. These propylene polymers or copolymers preferably have a melting peak of 110 ° C. or higher by DSC. When the melting peak by DSC is 110 ° C. or higher, good adhesion strength of the dried film to the substrate of the dispersion and good anti-blocking effect derived from the hardness of the film can be obtained. In addition, when a propylene-based polymer having a large amount of amorphous portion is used as a raw material, there is a high possibility of dissolving or swelling in a hydrocarbon-based solvent at room temperature, so that a solid content is large and a low-viscosity dispersion is obtained. It is difficult to obtain. Therefore, it is preferable to use a propylene polymer having a crystallinity of 30% or more as measured by X-ray.

The modified propylene polymer used in the present invention is obtained by modifying a propylene polymer with maleic anhydride, and at least a part of the maleic anhydride is half-ester or diesterified. Although the content of the maleic anhydride is not particularly limited, from the viewpoint of the adhesive strength of the dried film to the substrate, the total amount of the maleic anhydride-modified propylene polymer is
Preferably it is 0.1 to 10% by weight. The method of esterifying maleic anhydride in a propylene polymer modified with maleic anhydride is not particularly limited, but preferably, the propylene homopolymer or copolymer is converted to an aromatic hydrocarbon or a halogenated hydrocarbon. It is preferred that the mixture be dissolved in a hydrogen solvent by heating and stirring, and maleic anhydride and an organic peroxide are successively added and reacted, and then reacted with an alcohol for esterification. Since the esterification proceeds simply by heating the modified propylene polymer and the alcohol without using a catalyst such as an amine, the mixture of the hydrocarbon-based medium and the alcohol is used when producing the dispersion. Then, the propylene polymer modified with maleic anhydride is heated and stirred for a certain period of time to perform dissolution and esterification, and then cooled to precipitate polymer particles as described later. Examples of the alcohol to be esterified include aliphatic alcohols such as methanol, ethanol, isopropyl alcohol and n-butanol; dihydric alcohols such as ethylene glycol and diethylene glycol; and trihydric or higher alcohols such as glycerin, sorbitol and pentaerythritol. Can be
From the relationship between the solid content and the viscosity of the resulting dispersion, an aliphatic alcohol having 1 to 4 carbon atoms is preferred. The esterification rate of maleic anhydride is usually 10 to 100%, preferably 15 to 100%, based on the bound maleic anhydride.
%, More preferably 20 to 100%, and the higher the esterification rate, the higher the solid content and the lower the viscosity of the dispersion.

The average particle size of the esterified modified propylene polymer in a hydrocarbon medium is usually from 0.1 to 10 μm, preferably from 0.3 to 5 μm. If the particle size is less than 0.1 μm, a dispersion having a low viscosity and a high solid content cannot be obtained. On the other hand, if it exceeds 10 μm, the resin particles settle with the lapse of time during storage, which impairs the workability. The propylene copolymer modified with maleic anhydride (derivative) disclosed in JP-A-1-74536 and JP-A-1-74537 is soluble in an organic solvent having a low molecular weight and a low crystallinity. And the configuration is different from the present invention. Further, there is no disclosure of the effect of the modified polyolefin itself using the maleic anhydride ester.

[0008] The hydrocarbon-based medium that can be used in the present invention is not particularly limited as long as the modified propylene polymer can be maintained in a dispersed state. Examples thereof include benzene, toluene, xylene, and cyclohexane. ,
Normal paraffin, isoparaffin, mineral spirit and the like can be mentioned, and toluene and isoparaffin are preferable. This hydrocarbon-based oil may be the same as the solvent used in the maleic anhydride modification step, or may be different. In such a hydrocarbon-based solvent, the esterified modified propylene polymer obtained as described above is dissolved by heating and stirring, and then the temperature is lowered, and the temperature is maintained for a certain time near the temperature at which the modified propylene polymer precipitates. The modified propylene polymer dispersion of the present invention can be obtained by maintaining the temperature below room temperature for a certain period of time and then returning the temperature to room temperature. At this time, a desired average particle size can be obtained by appropriately selecting the weight ratio of the modified propylene polymer to the hydrocarbon-based solvent, the temperature and the holding time thereof, the number of rotations of stirring, and the like. A preferred ratio of the modified propylene polymer to the hydrocarbon-based medium is 5:95 to 25:75 by weight, more preferably 10: 9.
0:20:80. Also, a suitable temperature holding time is
It takes 0.5 to 5 hours near the deposition temperature of the modified propylene polymer and 0.5 to 5 hours at a temperature lower than room temperature. The modified propylene polymer dispersion of the present invention is a dispersion in which the modified propylene polymer is dispersed in the hydrocarbon-based medium in a solid state, and the alcohols and acetates described above within a range not impairing the effects of the present invention. , Ketones and ethers can be used in combination.

[0009]

The present invention will be described below with reference to examples. Example 1 (Modification of propylene polymer with maleic anhydride) Propylene having an ethylene content of 4.5% by weight, a peak temperature of melting by DSC of 137 ° C., and a crystallinity by X-ray of 50%. 100 parts by weight of the ethylene copolymer and 700 parts by weight of monochlorobenzene were charged into an autoclave having a volume of 100 l, and dissolved by stirring while heating to 130 ° C. Next, 5/3 parts by weight of benzoyl peroxide and 5 parts by weight of maleic anhydride were added in three portions every hour, for a total of 5 parts by weight. After adding the whole amount, the mixture was further stirred at the same temperature for 1 hour and held. did. Thereafter, the temperature was lowered to 50 ° C., 300 parts by weight of methyl ethyl ketone was charged, then the mixture was extracted and centrifuged to obtain a propylene polymer to which 1.3% by weight of maleic anhydride was added. (Esterification of maleic anhydride in propylene polymer) Subsequently, 6 parts by weight of ethanol and 800 parts by weight of toluene were charged to a 50-liter autoclave with respect to 200 parts by weight of the propylene polymer modified with maleic anhydride. After heating and stirring at 100 ° C. for 3 hours, acetone was added, the temperature was lowered to room temperature, and the mixture was extracted to obtain a maleic anhydride of modified propylene. When examined by infrared absorption spectrum, the peak of maleic anhydride disappeared,
All were found to be esterified (esterification rate 100%). (Preparation of Modified Propylene Polymer Dispersion) Next, 20 parts by weight of the esterified modified propylene polymer and 80 parts by weight of toluene were put into a 1-liter flask equipped with a cooling tube,
After heating and stirring at 80 ° C. for 30 minutes to dissolve, the temperature was lowered to 60 ° C., and the solution was stored at 400 rpm for 2 hours. As a result, the solution became slightly opaque. Further, the number of rotations was increased to 500 rpm, the liquid temperature was cooled at 10 ° C., and further maintained for 2 hours.
Upon returning to room temperature, a rainbow white dispersion was obtained. When the average particle size of this dispersion was examined with a microscope,
It was found to be 0.7 μm. The solid concentration is 2
0% by weight and measured at 25 ° C. using a Brookfield (BL) type viscometer. As a result, the viscosity was 270 cps. Furthermore, the obtained dispersion was put in a sealed glass bottle, left at room temperature for 3 months, and the viscosity was measured again by the above method. The viscosity was 300 cps, and the storage stability was excellent without sediment. Was.

Comparative Example 1 The same operation as in Example 1 was carried out except that 20 parts by weight and 80 parts by weight of toluene were used without esterification of the propylene polymer modified with maleic anhydride used in Example 1. An attempt was made to obtain a dispersion, but the dispersion gelled before the liquid temperature reached 10 ° C., and a dispersion was not obtained.

Example 2 (Modification of propylene polymer with maleic anhydride) The 1-butene content was 4.8% by weight, the ethylene content was 2.7% by weight, the peak temperature of melting by DSC was 136 ° C. 100 parts by weight of a propylene / ethylene / 1-butene terpolymer having a crystallinity of 52% by X-ray, 10 parts by weight of maleic anhydride and 500 parts by weight of xylene are placed in a flask equipped with a cooling tube, and refluxed with xylene. Under the temperature (about 140 ° C.), 25 parts by weight of a xylene solution containing 20% by weight of dicumyl peroxide was added dropwise over 3 hours.
It was kept at 0 ° C. for 1 hour (at this point a small sample was taken, washed with acetone, dried and the content of bound maleic anhydride was determined to be 2.3% by weight). (Esterification of maleic anhydride in propylene polymer) Subsequently, 10 parts by weight of isopropyl alcohol was added to the obtained maleic anhydride-modified propylene polymer,
After holding at 140 ° C. for 1 hour, the temperature was lowered to 50 ° C.
The whole amount was put into parts by weight of acetone, and the solvent was removed while rinsing 1,000 parts by weight of acetone in a centrifuge, and the obtained resin powder was dried. When the infrared absorption spectrum was examined, a peak specific to maleic anhydride and its ester was confirmed. From the content of maleic anhydride, the esterification rate was 2%.
It turned out to be 0%. (Preparation of Modified Propylene Polymer Dispersion) Next, 12 parts by weight of this esterified modified propylene polymer and 88 parts by weight of toluene were placed in a 1-liter flask, and dissolved by heating at 80 ° C. for 30 minutes with stirring. Thereafter, a dispersion was obtained in the same manner as in Example 1, and the average particle size was 2 μm, and BL type 25 was obtained.
The viscosity at 60 ° C. was 60 cps, and the viscosity after standing at room temperature for 3 months as in Example 1 was 27 cps, indicating good storage stability without sediment.

Comparative Example 2 Esterification ratio of 20 obtained in the esterification step of Example 2
% Of a modified propylene polymer and 88 parts by weight of toluene were placed in a 1-liter flask, and heated and stirred at 80 ° C. for 30 minutes to dissolve. Then, the mixture was cooled to room temperature at a rotation speed of 50 rpm to obtain a dispersion. The average particle size of this dispersion is 15 μm.
m, viscosity of BL type at 25 ° C immediately after being obtained is 300 cps
However, after 3 days, it gelled and the viscosity could not be measured.

Comparative Example 3 14 parts by weight of a propylene polymer modified with maleic anhydride before esterification obtained in Example 2 and toluene 86
A dispersion was obtained in the same manner as in Example 1, except that parts by weight were used. The average particle size of the obtained dispersion was 0.5 μm, and the viscosity at 25 ° C. of the BL type was 760 cps. Further, the viscosity after being left at room temperature for 3 months as in Example 1 was 12000 cps, and the viscosity increased with time.

Comparative Example 4 As a raw material of the modified propylene polymer, the ethylene content was 5.4% by weight, and the melting peak temperature by DSC was 133.
Modified with maleic anhydride having a maleic anhydride content of 1.5% by weight in the same manner as in Example 1 except that a propylene copolymer having a crystallinity of 37% at 37 ° C. and X-rays was used. A propylene polymer was obtained. When the modified propylene polymer was esterified by the same operation as in Example 1,
100% esterified. Further, 88 parts by weight of the esterified modified propylene polymer and 12 parts by weight of toluene were placed in a 1-liter flask, and the same operation as in Example 1 was carried out.
A modified propylene polymer dispersion was obtained. The resulting dispersion is a nearly transparent liquid having an average particle size of 0.05 μm or less.
The viscosity at 25 ° C. of the L-form was as high as 7200 cps, and it gelled when left for one day.

[0015]

According to the present invention, it is possible to obtain a modified propylene polymer dispersion in which the viscosity does not change with time during storage and the viscosity is low and the workability is good even if the solid content is high.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhide Hayama 1, Toho-cho, Yokkaichi-shi, Mie Prefecture Mitsubishi Yuka Co., Ltd. (72) Inventor Yasuo Kitani 1, Toho-cho, Yokkaichi-shi, Mie Mitsubishi Yuka (56) References JP-A-4-183739 (JP, A) JP-A 64-1750 (JP, A) JP-A-63-6040 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 3/00-3/28 C08L 1/00-101/16

Claims (1)

(57) [Claims] 1. A modified propylene polymer particle in which at least a part of maleic anhydride is esterified and has an average particle size of 0.1 to 10 μm in a propylene polymer modified with maleic anhydride, A modified propylene polymer dispersion dispersed in a system medium.