JPS6366845B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a modified polypropylene resin molding material and a method for producing the same. More specifically, the present invention relates to a modified polypropylene resin molding material modified with an α,β unsaturated carboxylic acid or a derivative thereof, which has properties suitable for composites with other materials, and has excellent impact resistance, and a method for producing the same. Polypropylene resin is used in large quantities as a general-purpose resin due to its excellent properties, but in recent years, as a means to further improve its performance, it has been combined with other materials, such as increasing rigidity by combining with inorganic fillers. It has been used in a wide variety of applications, including composite materials with excellent heat resistance, and composite films that are combined with other resin films. When combining with these other materials, if polypropylene resin is used as it is, the effect of the combination will be small due to the surface inert properties of polyolefin resin, but it is necessary to treat polypropylene resin by appropriate means. It is also well known that significant effects can be obtained by modification. α,β unsaturated carboxylic acid or derivative thereof (hereinafter, this may be simply referred to as α,β unsaturated carboxylic acid) in polyolefin resin
The method of grafting and modifying resin has been used for a long time, and the modified resin increases adhesion and affinity with inorganic fillers, other types of resin, or structural materials such as steel plates. , is known to exhibit excellent performance as a composite material. Regarding the modification of polypropylene resin, a modification method using polypropylene resin, α, β unsaturated carboxylic acids, and a radical reaction initiator has been proposed. However, in these methods, α, β
When attempting to increase the grafting ratio of unsaturated carboxylic acids to the backbone polymer, it is necessary to use a relatively large amount of radical reaction initiator, and as a result,
When using a polypropylene resin based on propylene homopolymer or ethylene propylene random copolymer, there is a drawback that molecular chain scission tends to occur and the flow index of the resin becomes too large. When using block copolymers or copolymer compositions with excellent impact resistance called copolymerization, especially those containing ethylene propylene copolymers with a large molecular weight, there is a drawback that gel formation occurs. It was something I couldn't escape. The generation of this second gel causes various negative effects such as deteriorating the surface condition of the molded product and decreasing the elongation rate, but in particular, it significantly reduces the impact strength of the modified polypropylene resin. This was a major difficulty. In other words, composite materials obtained by combining polypropylene resin with materials such as inorganic fillers or metals have high rigidity but low impact resistance, so modified polypropylene resins with better impact resistance are required. In the above methods, even if a so-called ethylene-propylene block copolymer, which has excellent impact resistance, is used as a polypropylene resin as a raw material for modification, a product with high impact strength cannot be obtained. Of course, by reducing the amount of the radical reaction initiator, the generation of gel can be suppressed, but on the other hand, the grafting rate and grafting efficiency of α,β unsaturated carboxylic acids are reduced. Therefore, it has not been possible to obtain a modified polypropylene resin that has been modified with a sufficient grafting rate and has a high level of impact strength. As a result of intensive research focusing on this point, the present inventors found that by performing the grafting reaction under special conditions, a high grafting rate that could not be obtained conventionally,
The present invention was achieved by successfully producing a modified polypropylene resin molding material with impact resistance. The gist of the invention is to include a polypropylene part and an ethylene propylene copolymer part with an ethylene unit content of 20 to 80% by weight, the intrinsic viscosity of the polypropylene part is 1.4 to 3 dl/g, and the content of the part is 70% by weight. % by weight or more, the intrinsic viscosity of the ethylene propylene copolymer part is 4 dl/g or more, the content of this part is 2 wt% or more, and the total ethylene unit content is 5 wt% or more. For 100 parts by weight of polymer or copolymer composition,
α, β unsaturated carboxylic acid or its derivative 0.03~
10 parts by weight, 0.005 to 1 part by weight of a radical reaction initiator, and 0.03 parts by weight or more of water are mixed and melt-kneaded. the melt flow index is 0.2 to 50 g/10 min, and the amount of the grafted α,β unsaturated carboxylic acid or derivative thereof is 0.03 to 5% by weight;
The present invention also provides a method for producing a modified polypropylene resin molding material that does not substantially contain a gel component. To explain the present invention in more detail, the raw materials for producing the modified polypropylene resin molding material of the present invention are molding materials commonly referred to as block copolymer grade in the polypropylene industry, with a polypropylene portion and ethylene unit content. contains 20 to 80% by weight of ethylene propylene copolymer part, and the intrinsic viscosity of the polypropylene part is
1.4 to 3 dl/g and the content of this part is 70% by weight or more, and the intrinsic viscosity of the ethylene propylene copolymer part is 4 dl/g or more and the content of this part is 2% by weight or more. , a block copolymer or copolymer composition having a total ethylene unit content of 5% by weight or more (hereinafter referred to as raw material resin)
is used. Of these, 75 are polypropylene parts.
~90% by weight ethylene propylene copolymer portion 3~
20% by weight and polypropylene part 0-20% by weight
and the content of total ethylene units is 7 to 20% by weight.
It is preferable that The intrinsic viscosity here is the value measured at 135°C in tetralin (the same applies below). Melt flow index of raw resin (2.16Kg, 230℃ according to ASTM-D-1238-57T)
(hereinafter abbreviated as MFI)
is 0.2 to 50 g/10 minutes, and the notched Izot impact strength at 20°C (measured according to ASTM-D-256, the same applies below) is 10 Kgcm/10 minutes.
It is preferable that it is not less than cm. As the polypropylene portion of the raw material resin, a propylene homopolymer or an ethylene-propylene random copolymer having an ethylene unit content of 2 mol % or less and an intrinsic viscosity of 1.4 to 3 dl/g is used. The ethylene propylene copolymer portion has an ethylene unit content of 20 to 80% by weight and an intrinsic viscosity of 4 dl/g or more, preferably 5 to 15
A random copolymer with a dl/g is used. As the polyethylene part, ethylene homopolymer or ethylene unit content is 93 mol%
A random copolymer of ethylene and other α-olefin, preferably 95 mol% or more, is used. The intrinsic viscosity of the polyethylene portion is preferably 2 dl/g or more, particularly 2 to 12 dl/g. As such a raw material resin, a commercially available product may be used, but it may also be one produced by a known method for producing a block copolymer grade of polypropylene. That is, the polypropylene portion, the ethylene propylene copolymer portion, and optionally the polyethylene portion may be produced in any order by performing two-step polymerization or three-step polymerization on the same catalyst system, or the polypropylene portion and the polyethylene portion may be produced in any order. The ethylene propylene copolymer portion is a blend of a copolymer produced on the same catalyst system with polyethylene produced using another catalyst system and polymerization equipment, or a two-component or three-component copolymer produced using separate catalyst systems, polymerization It may be produced using a device and blended. Most preferred, however, are those in which the polypropylene portion and the ethylene propylene copolymer portion are prepared on the same catalyst system. On the other hand, α,β unsaturated carboxylic acids or their derivatives, which are another raw material component, include maleic acid, acrylic acid, methacrylic acid, and their acid anhydrides, alkyl esters, and aryl esters, specifically maleic acid , maleic anhydride, acrylic acid, acrylic acid methyl ester, methacrylic acid, methacrylic acid methyl ester, etc. Maleic acid and maleic anhydride are preferred. The radical reaction initiator is not particularly limited as long as it can initiate a radical reaction, but specifically,
αα′ bistersially-butylperoxyp-diisopropylbenzene, 2,5 dimethyl 2,5 di(tert-butylperoxy)hexane, 2,
Examples include 5 dimethyl 2,5 di(tert-butyl peroxy)hexyne-3, di tert-butyl peroxide, 2,5 dimethylhexane 2,5 dihydroperoxide, and dicumyl peroxide. The modified polypropylene resin molding material of the present invention is produced by melt-kneading raw resin, α,β-unsaturated carboxylic acids, a radical reaction initiator, and water. It is desirable to mix each component before performing the kneading reaction. The amount of each ingredient used is
It is necessary to change it depending on the required amount of grafting and the properties of the raw material resin, so it cannot be stated unconditionally,
0.03 to 10 parts by weight, preferably 0.03 to 2 parts by weight, particularly preferably 0.05 to 1 part by weight, radical reaction initiator
0.005 to 1 part by weight, preferably 0.01 to 0.5 part by weight, water
The amount is 0.03 parts by weight, preferably 0.03 to 5 parts by weight, particularly preferably 0.05 to 1 part by weight. If the amount of α,β unsaturated carboxylic acids is less than 0.03 parts by weight, the denaturing effect will not be sufficient, and if the amount of water is less than 0.03 parts by weight, gel components will be generated, which are both undesirable. If the amount of water exceeds 5 parts by weight, foaming occurs during denaturation, resulting in poor workability, so it is preferably 5 parts by weight or less. The kneading reaction can be carried out using a Banbury mixer, an extrusion molding machine, etc. at a temperature higher than the melting point of the raw material resin. The temperature is preferably 180 to 250°C, although it depends on the properties of the radical reaction initiator. Further, the reaction time is not particularly limited, but it is preferably about 20 seconds to 5 minutes; a long reaction time is not preferable because the polymer deteriorates. Of course, when carrying out this graft reaction, it is also possible to take into account conventionally known methods, and it is also possible to carry out the graft reaction and mixing of the inorganic filler at the same time, or by adding an appropriate auxiliary agent. Although it is possible to measure the stability of modified polypropylene, care must be taken not to impede the effect of water, which is a feature of the present invention. As described above, MFI is 0.2 to 50 g/10 minutes, preferably 0.5 to 20 g/10 minutes, particularly preferably 1 to 10
g/10 min, the content of the grafted α,β unsaturated carboxylic acids in the modified polypropylene resin molding material is 0.03 to 5% by weight, preferably 0.05 to 2% by weight.
Particularly preferably 0.05 to 1% by weight, a modified polypropylene resin having a notched Izo impact strength at 20° C. of 10 Kg·cm/cm or more, preferably 12 Kg·cm/cm or more, and substantially containing no gel component. A molding material is obtained. Here, the gel component is measured by extracting the modified polypropylene resin molding material in boiling xylene, determining the weight fraction of the undissolved portion, and determining the gel fraction. "No" means that the gel fraction is 2% by weight or less, particularly 1% by weight or less, and more preferably 1% by weight or less.
Refers to 0.5% by weight or less. Therefore, the modified polypropylene resin molding material obtained by the production method of the present invention has a relatively high grafting amount of α,β unsaturated carboxylic acids of 0.03 to 5% by weight, in other words, the degree of modification is relatively high. It is an impact-resistant polypropylene resin molding material that does not substantially contain gel components in large areas,
It is suitable for combination with other materials. Hereinafter, the present invention will be explained in more detail with reference to Examples. In the following, the amount of grafted α,β unsaturated carboxylic acid or its derivative (grafting amount) is expressed as the content (wt%) in the molding material. is measured by infrared absorption spectroscopy and expressed as the grafting rate. Example 1 (1) Production of block copolymer A solid titanium trichloride catalyst complex was synthesized by precipitating a heptane solution obtained from titanium tetrachloride, dioctyl ether, and ethyl aluminum monochloride at elevated temperatures. Using this solid titanium trichloride catalyst complex and diethylaluminium monochloride, (a) 1st stage propylene homopolymerization in the coexistence of hydrogen at a polymerization temperature of 70°C (b) 2nd stage coexistence of ethylene and hydrogen at a polymerization temperature of 50°C Ethylene-propylene random copolymerization (c) Third stage A three-stage ethylene homopolymerization in the coexistence of hydrogen at a polymerization temperature of 70°C was carried out. The first and second stages were polymerization in liquid propylene, and the third stage was gas phase polymerization. Sampling of the polymer and gas replacement were performed at intermediate stages of each stage. From the analysis of polymerization conditions and sample analysis, the obtained block copolymer had an MFI of 1.9.
g/10 min, total ethylene unit content = 13.5
% by weight, and its composition is as shown in Table 1.

[Table] (2) Production of modified polypropylene resin molding material To 100 parts by weight of the block copolymer obtained in (1) above, 0.1 part by weight of maleic anhydride, αα′bistershaributylperoxy-p-isopropylbenzene Mix 0.01 part by weight and 0.1 part by weight of water,
A kneading reaction was carried out using a 30 mmφ, L/D=23 single-screw extruder equipped with a Dalmage screw. The resin temperature was a final 230°C and the residence time was about 1.5 minutes. The obtained modified polypropylene resin molding material had an MFI of 3, a maleic anhydride grafting rate of 0.055% by weight, a gel fraction of 0.1% by weight, and a notched Izot impact strength of 13.5 kg.
It was extremely high (cm/cm). Examples 2 to 8 Example 1 except that the amounts of each component or the type and amount of radical reaction initiator were as shown in Table 3.
It was denatured in the same way. Table 3 shows the measurement results for the obtained modified polypropylene resin molding material.
Shown below. Example 9 (1) Production of block copolymer A three-stage polymerization was carried out using the method described in Example 1 (1), and the results shown in Table 2 were obtained at MFI = 6 g/10 min and total ethylene unit content of 11% by weight. A block copolymer of the following composition was prepared.

[Table] (2) Production of modified polypropylene resin molding material Modification was carried out in the same manner as in Example 1, except that the block copolymer produced as described in (1) above was used. Table 3 shows the measurement results for the obtained modified polypropylene resin molding material. Example 10 Modification was carried out in the same manner as in Example 1 except that acrylic acid was used instead of maleic anhydride. Table 3 shows the measurement results for the obtained modified polypropylene resin molding material. Comparative Examples 1 to 6 Kneading was carried out in the same manner as in Examples 1 and 9, except that α,β unsaturated carboxylic acids, radical reaction initiators, and water were not added (Comparative Examples 1 and 4). Further, denaturation was carried out in the same manner as in Examples 1, 5, 9, and 10 except that water was not added. Table 3 shows the measurement results for the obtained modified polypropylene resin molding material. Comparative Example 7 (1) Production of block copolymer A three-stage polymerization was carried out using the method described in Example 1 (1), and the results shown in Table 4 were obtained at MFI = 7 g/10 minutes and total ethylene unit content of 4% by weight. A block copolymer of the following composition was prepared.

[Table] (2) Production of modified polypropylene resin molding material Modification was carried out in the same manner as in Comparative Example 2, except that the block copolymer produced as described above was used. Table 3 shows the measurement results for the obtained modified polypropylene resin molding material.
Although no gel components were generated, the impact strength was not high either. Comparative Example 8 (1) Production of block copolymer Polymerization was carried out using the method described in Example 1 (1),
MFI=5g/10min, total ethylene unit content 14
A block copolymer having the composition shown in Table 5 in weight percent was prepared.

[Table] (2) Production of modified polypropylene resin molding material Modification was carried out in the same manner as in Example 1 (2). The measurement results are shown in Table 3. No gel was formed on the modified polypropylene, but the impact strength was low.

[Table] Example 11 (1) Production of block copolymer A copolymer was produced in the method of Example 1 by omitting the third step of ethylene homopolymerization. The obtained block copolymer had an MFI of 3.6, a total ethylene unit content of 6.5% by weight, and a composition as shown in Table 6.

[Table] (2) Production of modified polypropylene resin molding material Example 5 using 100 parts by weight of the copolymer of (1) above
Denaturation was performed under the following conditions. The obtained modified polypropylene had an MFI of 28, an amount of grafted maleic anhydride of 0.16% by weight, and a gel component of 0.2% by weight. The Izot strength of the same resin is 11
It was Kg・cm/cm. Comparative Example 9 Modification was carried out under the same conditions as in Example 11 (2) except that water was not added. The obtained modified polypropylene is
MFI=20, amount of grafted maleic anhydride 0.17
% by weight, and the gel component was 2.2% by weight.
The resin had an Izot strength of 9 kg·cm/cm.

Claims (1)

[Scope of Claims] 1. Contains a polypropylene portion and an ethylene propylene copolymer portion having an ethylene unit content of 20 to 80% by weight, and the intrinsic viscosity of the polypropylene portion is
1.4 to 3 dl/g and the content of this part is 70% by weight or more, and the intrinsic viscosity of the ethylene propylene copolymer part is 4 dl/g or more and the content of this part is 2% by weight or more. , 0.03 to 10 parts by weight of an α,β unsaturated carboxylic acid or a derivative thereof, and 0.005 parts by weight of a radical reaction initiator, per 100 parts by weight of a block copolymer or copolymer composition having a total ethylene unit content of 5% by weight or more. -1 part by weight and 0.03 part by weight or more of water are mixed and melt-kneaded, the melt flow index is 0.2 to 50 g/10 minutes, and the grafted α,β unsaturated carboxylic acid or its derivative is The amount is 0.03 to 5% by weight,
A method for producing a modified polypropylene resin molding material that does not substantially contain a gel component. 2. The block copolymer or copolymer composition is
The manufacturing method according to claim 1, which contains a polyethylene portion in addition to the polypropylene portion and the ethylene-propylene copolymer portion.