JPH0570643B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to ionically crosslinkable compositions. Chlorinated polyolefins, which are chlorinated products of polyolefins such as polyethylene and ethylene-propylene copolymers, have excellent weather resistance, heat resistance, and mechanical properties as rubbers, and are widely used for various purposes. There is. However, its structure is essentially the same as polyolefin and does not have double bonds or other functional groups that can serve as crosslinking points, so peroxide crosslinking, electron beam crosslinking, or the use of very special crosslinking agents are required. There is a problem in that only special crosslinking means such as this can be used. Therefore, the present inventors conducted intensive studies on chlorinated polyolefins that can be used as a more versatile crosslinking means, and as a result, they arrived at the present invention. That is, the present inventors have developed a chlorinated polyolefin copolymer obtained by copolymerizing maleic anhydride and chlorinating it, or converting some or all of the maleic anhydride groups in the copolymer into dicarboxylic acid or half ester. The modified chlorinated polyolefin copolymer is
It has been discovered that crosslinked products obtained from compositions consisting of these chlorinated polyolefin copolymers and modifiers exhibit excellent crosslinking properties against modifiers such as alkali metal salts, and have excellent crosslinked physical properties. ,
Based on this, the present invention was completed. That is, the present invention provides (A) a chlorinated product of a copolymer obtained by copolymerizing α-olefin and maleic anhydride as essential components, the degree of chlorination being 5 to 50% by weight.
A chlorinated polyolefin-based copolymer of A chlorinated polyolefin copolymer partially or entirely modified with dicarboxylic acid and/or half ester and having a degree of chlorination of 5 to 50% by weight, and (C) an alkali metal, an alkaline earth metal, and a transition metal. A modifier consisting of a metal salt or a base selected from the group consisting of: (A) or (B) 0.5~ of acid groups and modified maleic anhydride groups
The present invention resides in an ionic crosslinkable composition characterized in that it is formulated in a 5-fold molar amount. A copolymer obtained by copolymerizing α-olefin and maleic anhydride as essential components in the chlorinated polyolefin copolymer (A) above (hereinafter referred to as an olefin copolymer) can be prepared by various known methods. α-olefin and maleic anhydride may be copolymerized, but alkyl methacrylate or alkyl acrylate [hereinafter referred to as (meth)
An olefin-based copolymer obtained by copolymerizing α-olefin and maleic anhydride in the presence of an alkyl acrylate is preferred. Examples of α-olefins include ethylene, propylene, butene-1, isobutylene, pentene-1
Examples include 1,2-methyl-butene-1, 3-methyl-butene-1, hexene-1, heptene-1, octene-1, etc. Among these, ethylene is preferred, and two or more of these are preferred. It is also possible to use Examples of alkyl (meth)acrylates include compounds represented by the following formula ().

[In the above formula, R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. ]

Specific examples of compounds encompassed by this formula include methyl (meth)acrylate, (meth)
Examples include ethyl acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. A preferred example of such an olefin copolymer is a copolymer represented by the following formula ().

[In the above formula, R' and R'' are hydrogen atoms or alkyl groups having 1 to 10 carbon atoms, R ¹ and R ² are the same as in the above formula (), m ₁ , m ₂ and m ₃ are copolymer It is preferable to indicate the mol% of each unit in the combination and satisfy the following relationships (1) to (4).]

(1) m ₁ + m ₂ + m ₃ = 100 (2) 45≦m ₁ ≦99.9 (more preferably 80≦m ₁ ≦98) (3) 0≦m ₂ ≦50 (4) 0.1≦m ₃ ≦5 ( More preferably 0.5≦m ₃ ≦3) When m ₃ is less than 0.1 mol%, the crosslinking point concentration becomes too low, so when it is chlorinated as described below and used as a component in the composition of the present invention. , it is difficult for the composition to exhibit practical crosslinking properties. On the other hand, if m ₃ exceeds 5 mol %, the physical properties may deteriorate, leading to an increase in costs and the economic merits may be lost. When using alkyl (meth)acrylate,
The amount should be adjusted appropriately depending on the amount of maleic anhydride used, and as mentioned above, the mol% in the copolymer
The content is preferably 50 mol% or less and 2 mol% or more. Specific examples of the above olefin copolymer include:
Ethylene-maleic anhydride copolymer, ethylene-
Examples include methyl methacrylate-maleic anhydride copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer, and the like. The chlorinated polyolefin copolymer (A) used in the present invention can be obtained by chlorinating the polyolefin copolymer described above. The chlorine content of the chlorinated polyolefin copolymer (hereinafter simply referred to as modified polyolefin) should be 5 to 5, taking into consideration rubber-like properties, transparency, flexibility, etc., and for the purpose of obtaining the desired crosslinked product of the present invention. 50% by weight
Considering processability, thermal stability, other physical properties, etc., the content is preferably 25 to 40% by weight. The method for obtaining a modified polyolefin by chlorinating the above-mentioned olefin-based copolymer can be carried out by various known methods, and any of the conventional solution methods, water suspension methods, and other methods can be used. However, some of the present inventors previously disclosed a preferred method for obtaining such modified polyolefins in Japanese Patent Application No.
- Proposed in No. 159643. Next, the modified chlorinated polyolefin copolymer as component (B) will be explained. This modified chlorinated polyolefin copolymer is a chlorinated product of the above olefin copolymer, and is obtained by modifying the acid anhydride group (maleic anhydride group) in the above copolymer. It is. It does not matter whether the chlorination and the above-mentioned modification are carried out before or after. That is, the chlorinated product may be modified after chlorinating the olefin copolymer, chlorination may be performed after modification, or chlorination and modification may be performed simultaneously. Modification is carried out, for example, by hydrolysis and/or half-esterification with alcohol, and the olefin copolymer before and after chlorination may be reacted with water and/or alcohol under heat. A preferred example of such a modified chlorinated polyolefin copolymer is shown in the following formula (). However, it is shown in a non-chlorinated state.

[Chemical formula] However, in the above formula, R′, R″, R ¹ and R ² are the above ()
Same as the formula, R ³ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, m ₁ , m ₂ , m' ₃ and m ₄ represent the mole% of each unit in the copolymer, It is preferable that the following relationships (a) to (c) are satisfied. (a) m ₁ +m ₂ +m′ ₃ +m ₄ =100 (b) 0.1≦m′ ₃ +m ₄ ≦5 (preferably 0.5≦m ₃ ′+m ₄
≦3) (c) m ₄ ≦5 (preferably 0.5≦m ₄ ≦3) Note that m ₁ and m ₂ are the same as in the above formula (). or
There are also cases where m′ ₃ =0 and m ₄ =5. Specific examples of the alcohol (R ³ OH) used for denaturation include primary alcohols such as methanol, ethanol, propanol, and butanol. The degree of modification of the dicarboxylic acid or half ester of the maleic anhydride group is arbitrary, but the above is preferred in consideration of workability and desired physical properties of the crosslinked product. Generally, the more acid anhydride groups there are, the more rapidly ionic crosslinking occurs, so the crosslinking treatment time can be shortened, but if kneading with the modifier is not done at low temperatures and crosslinking progresses at this stage, workability will decrease. Also, the crosslinking reaction does not proceed uniformly. On the other hand, the higher the degree of modification of the dicarboxylic acid or half ester, the longer the crosslinking treatment will take, but the kneading becomes easier and the crosslinking reaction proceeds more uniformly. The degree of chlorination and the method of chlorination of the modified chlorinated polyolefin copolymer can be carried out in the same manner as for the chlorinated polyolefin copolymer of component (A). The melting index of the chlorinated polyolefin copolymers of component (A) and component (B) is at 180°C and a load of 2.16 kg.
The rate is 0.05 to 1000 g/10 minutes, preferably 0.1 to 500 g/10 minutes. If the melting index is low, the temperature will rise during kneading with the modifier, resulting in crosslinking and hardening of the composition, which will likely lead to a decrease in workability. In addition, in the above example, the chlorinated polyolefin copolymer exemplified by the formula () is obtained by modifying the copolymer shown by the formula ().

The [Formula] moiety may be copolymerized as an independent copolymerization component (eg, maleic ester) without modifying the maleic anhydride group. For example, α-olefin,
The four components of alkyl (meth)acrylate, maleic anhydride, and maleic ester may be copolymerized. Specific examples of modifiers used in the present invention include:
NaOH, KOH, _CH3ONa , LiOH,
CH ₃ CO ₂ Na, (CH ₃ CO ₂ ) ₂ Zn, (CH ₃ CO ₂ ) ₂ Mg,
( _CH3CO2 ) _2Ca , Ca(OH) ₂ , _Mg (OH) ₂ , Zn
(OH) ₂ and the like, and mixtures thereof may also be used. The modifier is preferably used in moles of 0.5 to 5 times, preferably 1 to 3 times the number of moles (m ₃ ) of maleic anhydride groups contained in the chlorinated polyolefin copolymer (A).
Used twice. If it is too small, the crosslinking reaction will not proceed. Similarly, the number of moles of maleic anhydride groups (m ₃ ′) contained in the chlorinated polyolefin copolymer (B)
The total number of moles (m _{3 '} +
m ₄ ) is used in an amount of 0.5 to 5 times, preferably 1 to 3 times, by mole. This modifier can be used by kneading the fine powder with the chlorinated polyolefin copolymer or modified polyolefin copolymer of (A) or (B) to form a composition, and then crosslinking it by heating. However, it is also possible to prepare a composition by sprinkling this as a solution on (A) or (B) and then kneading it. When kneading the modifier, it is desirable from the viewpoint of workability and the physical properties of the crosslinked product that crosslinking does not occur, and it is also desirable to carry out the mixing at a temperature below the temperature at which the chlorinated product (A) or (B) does not decompose. The temperature is preferably 100°C or lower, preferably 100°C or lower. Or
If (A) or (B) has a large molecular weight and requires a high temperature, it is best to knead for a short time. The ionic crosslinkable composition of the present invention can be processed through a normal rubber crosslinking process. The crosslinking temperature is 80 to 200°C, preferably 100 to 160°C.
It is ℃. Although the crosslinking reaction proceeds at temperatures below 80°C, the rate is slow and a long crosslinking time is required to obtain sufficient crosslinking properties, which is not practical. Furthermore, at temperatures above 200°C, the chlorinated polyolefin copolymer will decompose, making it impossible to obtain a practical crosslinked product. It is also possible to use stabilizers such as magnesium oxide or carbon black or inorganic fillers used in chlorinated polyolefins in the ionically crosslinkable composition of the present invention. Next, the present invention will be described in detail based on Reference Examples, Examples, and Comparative Examples. In the Examples and Comparative Examples, the physical properties such as strength of the press-crosslinked samples are shown below, but all are the results of measurements according to JIS K-6301. Reference Example 1 A reference example regarding the chlorination reaction is shown below. Ethylene-ethyl acrylate-maleic anhydride copolymer, a polyolefin copolymer with a melt index of 212 (g/10 minutes) made by copolymerizing 26.4 wt% ethyl acrylate and 4.0 wt% maleic anhydride.
A chlorination reaction was carried out by dissolving 150 g in 1350 g of carbon tetrachloride and blowing chlorine gas into the reaction vessel while heating it to 80°C. Here, chlorination can be determined by quantifying the amount of hydrochloric acid gas in the waste gas.
Blowing of chlorine gas was stopped when chlorination reached 35 wt%. After the reaction solution was cooled, hexane was used as a precipitation solvent to precipitate the polymer, and the polymer was purified by washing under hexane reflux conditions while exchanging hexane several times. This polymer was vacuum dried at 100° C. overnight and then used in the following examples as a modified polyolefin, which is a component of the present invention. Reference Example 2 A reference example regarding the hydrolysis reaction is shown below. 20g of the chlorinated polyolefin copolymer synthesized in Reference Example 1 was dissolved in 200ml of toluene, and
cc of water and triethylamine in an amount three times the mole of maleic anhydride were added, and the mixture was heated at 80° C. for 5 hours with forced stirring. Thereafter, hydrochloric acid was added to neutralize the mixture, and further hydrochloric acid was added until it became weakly acidic, and the mixture was left overnight. Thereafter, hexane was added as a precipitation solvent to precipitate the polymer, and the hexane was exchanged several times to wash the polymer. Then the polymer
It was vacuum dried at 40°C overnight. The hydrolysis rate was calculated from the decrease in absorption due to acid anhydride at 1760 cm ^-1 from IR measurements, and it was found to be 100% hydrolyzed. Reference Example 3 A reference example of the half-esterification reaction is shown below. 20 g of the chlorinated polyolefin copolymer synthesized in Reference Example 1 was dissolved in 200 ml of toluene, 100 ml of methanol and 1 ml of triethylamine were added, and the mixture was reacted for 6 hours under refluxing conditions of methanol. Thereafter, hexane was added as a precipitation solvent to precipitate the polymer, and the hexane was exchanged several times to wash the polymer. The polymer was then dried at 40°C overnight. The half esterification rate is determined by IR measurement.
Calculating from the decrease in absorption due to acid anhydride at 176 cm ^-1 , 70% of maleic anhydride was half-esterified. Examples 1 to 3, Comparative Example 1 30wt% of the modifier listed in Table 1 was added to the chlorinated polyolefin copolymer of Reference Example 1.
Using an aqueous solution, the amounts listed in Table 1 were added and kneaded for 3 minutes at 130°C in a Lapoplast mill. This composition was press-formed into a 1.5 mm thick sheet under the pressing conditions listed in Table 1, and its physical properties were measured. The results are shown in Table 1. As a comparative example, an example of the polymer before chlorination of Reference Example 1 was shown.

[Table] From Table 1 above, it can be seen that the permanent elongation of the comparative example was too large and its performance as a crosslinked rubber was poor. Examples 4 to 6 The results obtained in the same manner as Examples 1 to 3 using the chlorinated polyolefins of Reference Examples 2 and 3 are shown in Table 2 as Examples 4, 5, and 6, respectively.
Note that Example 4 used the chlorinated polyolefin of Reference Example 2, and Examples 5 and 6 used the chlorinated polyolefin of Reference Example 3.

【table】

Claims (1)

[Claims] 1 (A) A chlorinated copolymer made by copolymerizing α-olefin and maleic anhydride as essential components, with a degree of chlorination of 5 to 50% by weight, or a chlorinated polyolefin copolymer ( B) A chlorinated copolymer formed by copolymerizing α-olefin and maleic anhydride as essential components, in which part or all of the maleic anhydride groups in the chlorinated product are dicarboxylic acid and/or half A chlorinated polyolefin copolymer modified into an ester and having a degree of chlorination of 5 to 50% by weight, and (C) a salt of a metal selected from the group consisting of alkali metals, alkaline earth metals, and transition metals; or 0.5 of the maleic anhydride group or the maleic anhydride group and the modified maleic anhydride group in the chlorinated polyolefin copolymer (A) or (B). An ionic crosslinkable composition characterized in that it is formulated in a molar amount of ~5 times.