JPH11343372A - Polypropylene composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a formulation for compounding a polypropylene with a polyethylene terephthalate to give a polypropylene compsn. excellent in moldability, impact resistance, or the like, esp. a formulation for enabling scrap PET to be recycled and reused as a mixture. SOLUTION: This compsn. is prepd. by compounding (A) 60-95 pts.wt. polypropylene, (B) 40-5 pts.wt. polyethylene terephthalate, and (C) 1-12 pts.wt. ethylene-alkyl (meth)acrylate-glycidyl (meth)acrylate copolymer contg. 15-40 wt.% alkyl (meth)acrylate units and 1-15 wt.%. glycidyl (meth)acrylate units. The compsn. may further be compounded with (D) 1-10 pts.wt. ethylene-alkyl (meth) acrylate copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polypropylene composition having excellent moldability, impact resistance and the like. In particular, the present invention relates to a compounding and prescription of a general-purpose polypropylene molded product so that a recycled product of polyethylene terephthalate can be mixed and used.

[0002]

2. Description of the Related Art Polyethylene terephthalate is used in containers,
It is widely used in the fields of films, fibers and the like, and a large amount of scrap is generated from these molded products. In particular, the reuse of scrap from containers such as bottles and trays has become a major social problem. In recycling such scrap, in many cases, polyethylene terephthalate has a low molecular weight, and it is difficult to obtain a molded product having high mechanical strength, and it is necessary to wash the scrap.
As a result, since it contains a lot of water, there is a problem that it has to be dried before use. Despite these problems, reuse has begun in some areas, but the reuse rate is still low.

[0003] In view of such a situation, the present inventors have considered whether polyethylene terephthalate scrap can be reused by blending it with general-purpose polypropylene. When a small amount of polyethylene terephthalate is blended with polypropylene, it can be expected to improve the flexural modulus and reduce molding shrinkage, but there is a problem that other physical properties of polypropylene are significantly reduced. For example,
Adverse effects such as a significant decrease in elongation at break and impact strength, a decrease in moldability and a deterioration in the appearance of a molded product are observed.

It has been reported in JP-A-61-60744 that it is effective to incorporate a small amount of an epoxy group-containing copolymer in order to improve the moldability and appearance of a molded product in a composition of polypropylene and polyester. Are listed. In this proposal, since the blending ratio of polypropylene and polyester is very wide, and polybutylene terephthalate is mainly studied as polyester, a system in which a small amount of polyethylene terephthalate is blended with respect to a large amount of polypropylene, Only one
Examples are given only. According to the example, as the epoxy group-containing copolymer, ethylene-glycidyl methacrylate copolymer is used, and it is shown that the extrusion stability of the composition is improved and the appearance of the molded product is improved. However, the impact resistance is slightly improved.

In order to improve the impact resistance, an epoxy group-containing copolymer proposed above is used, and an unsaturated carboxylic acid or its anhydride or a grafted unsaturated epoxy compound is grafted as polypropylene. It is suggested in Japanese Patent Application Laid-Open Nos. 61-60746 and 1-213352 that this is necessary. For example, according to the latter, unmodified polypropylene is used, and ethylene
When a glycidyl methacrylate copolymer is used, a composition having sufficiently high impact strength has not been obtained.

[0006]

The method using such modified polypropylene cannot be expected to consume a large amount because of the high cost of modification, and therefore does not meet the purpose of treating a large amount of polyethylene terephthalate scrap. Therefore, the present inventors have studied and examined a formulation that can significantly improve the impact resistance as well as the moldability and appearance of molded products when polyethylene terephthalate is blended even when unmodified polypropylene is used. went. As a result, they have found a formulation for blending a specific terpolymer.

Accordingly, an object of the present invention is to provide a new formulation having improved moldability, impact resistance and the like in a polypropylene composition containing polyethylene terephthalate. In particular, a recycled polypropylene product is used as polyethylene terephthalate. It is to provide a prescription that can be performed.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a poly (ethylene terephthalate) comprising 60 to 95 parts by weight of polypropylene and
The content of the alkyl (meth) acrylate is 15 to 100 parts by weight per 100 parts by weight of the polymer component consisting of 0 to 5 parts by weight.
40% by weight, glycidyl (meth) acrylate content is 1 to
15% by weight of ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer 1-2
The present invention relates to a polypropylene composition containing 0 parts by weight. In the present invention, the composition further comprises (meth)
An ethylene / (meth) acrylic acid alkyl ester copolymer having an acrylic acid acrylic ester content of 15 to 40% by weight can be blended at a ratio of 1 to 10 parts by weight.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene used in the present invention is a propylene homopolymer obtained by polymerization in the presence of a stereospecific catalyst or a propylene-based propylene and another α-olefin such as ethylene. It is a copolymer. In the above copolymer, the α-olefin content is usually about 30 mol% or less, and may be a random copolymer or a block copolymer. In consideration of moldability and mechanical strength, such a polypropylene has a melt flow rate at 230 ° C. and a load of 2160 g of 0.1 to 100 g / 10 min, particularly 0.5 to 100 g / 10 min.
It is preferable to use one with 50 g / 10 minutes.

When a propylene homopolymer is used as the polypropylene, the composition of the present invention makes it possible to increase the flexural modulus and has a higher impact strength than the propylene polymer alone. It is also possible to obtain a composition. In particular, a propylene homopolymer or a composition in which a small amount of polyethylene terephthalate is blended with the propylene homopolymer has a high rigidity, but the impact resistance is not so good, but according to the present invention, it is possible to greatly improve this. Depending on the formulation, rigidity can be maintained at a high level.

Further, the polypropylene block copolymer comprises:
In general, the impact strength is large, but the molding shrinkage is large like the propylene homopolymer. When polyethylene terephthalate is added to this, the impact strength is remarkably reduced, but according to the present invention, the impact strength can be made close to that of the polypropylene block copolymer, and the molding shrinkage can be reduced.

The polyethylene terephthalate used in the present invention may not only be derived from a terephthalic acid unit and an ethylene glycol unit but also may contain a small amount of a copolymer component. Such a copolymer component is
For example, it may be contained in a proportion of 20 mol% or less, preferably 10 mol% or less of the whole monomer. 1 of the copolymer component
By way of example, for example, aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, 1,3-propanediol And aliphatic diols such as 1,4-butanediol, neopentyl glycol and diethylene glycol, and alicyclic diols such as cyclohexanedimethanol. Of course, a small amount of tricarboxylic or higher polycarboxylic acid or polyol may be copolymerized.

As the polyethylene terephthalate, those having an intrinsic viscosity of about 0.4 to 1.5 dl / g measured in orthochlorophenol at 25 ° C. can be used. In particular, those having a reduced molecular weight recovered from polyethylene terephthalate scrap and falling within such an intrinsic viscosity range and containing water can be used. However, in general, it is possible to obtain a composition having a high impact strength by using it dried, but it is possible to obtain a composition having a sufficiently large impact strength without performing strict drying such as in general molding of polyethylene terephthalate. It is possible to obtain a composition.

In the present invention, the content of the alkyl (meth) acrylate is 15 to 40% by weight, preferably 20 to 35% by weight, more preferably 25 to 35% by weight, in addition to the above-mentioned components comprising polypropylene and polyethylene terephthalate.
Weight%, glycidyl (meth) acrylate content is 1 to 1
5% by weight, preferably 2 to 10% by weight, of an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate terpolymer is blended. Even when the terpolymer has a (meth) acrylic acid alkyl ester content less than the above range or a copolymer containing no such ester component, excellent moldability and impact resistance are obtained. A composition having excellent properties cannot be obtained. Further, even if the (meth) acrylic acid alkyl ester content is larger than the above range, no further effect of improving physical properties can be expected, and adverse effects such as a decrease in flexural modulus and a decrease in heat resistance appear. Not preferred.

When a copolymer containing less than or not containing glycidyl (meth) acrylate in the above copolymer is used, a composition having sufficiently high impact strength cannot be obtained. . When a copolymer whose content is larger than the above range is used,
Excessive reaction with polyethylene terephthalate causes generation of bumps and gels, and a decrease in fluidity due to an increase in melt viscosity, and a composition excellent in appearance and moldability cannot be obtained.

Specific examples of the alkyl (meth) acrylate in the above copolymer include methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, and methacrylic. Examples thereof include isobutyl acid. Among them, about 1 to 10 carbon atoms,
In particular, it is preferable to use an alkyl ester having about 2 to 8 carbon atoms.

In order to maximize the modifying effect of the copolymer, the melt flow rate at 190 ° C. under a load of 2160 g is 0.1 to 100 g / 10.
It is preferable to use a material having a viscosity of about 1 to 50 g / 10 minutes.

In the present invention, the mixing ratio of polypropylene to polyethylene terephthalate is 60 to 95 for the former.
Parts by weight, preferably 70 to 90 parts by weight,
To 5 parts by weight, preferably 30 to 10 parts by weight (total of 10
0 parts by weight). If the blending ratio of polyethylene terephthalate is less than the above range, the flexural modulus of the composition will be small and the molding shrinkage will be large, so the advantage of blending polyethylene terephthalate will be reduced. On the other hand, if the compounding ratio is larger than the above range, the moldability, impact resistance and the like are reduced, and neither is preferable.
In addition, ethylene, alkyl (meth) acrylate,
The mixing ratio of the (meth) glycidyl acrylate copolymer is
Although it differs slightly depending on the polymerization composition, it is 1 to 20 parts by weight, preferably 2 to 10 parts by weight, per 100 parts by weight of the total amount of polypropylene and polyethylene terephthalate. That is, if the compounding amount is too small, it is difficult to obtain a composition having good impact resistance, and if the compounding amount is too large, a composition having good flexural modulus, heat resistance, etc. cannot be obtained. .

In the present invention, a three-component composition comprising polypropylene, polyethylene terephthalate, and an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer is further added to an alkyl (meth) acrylate. An ethylene / (meth) acrylic acid alkyl ester copolymer having a content of 15 to 40% by weight, preferably 20 to 35% by weight,
1 to 10 parts by weight, preferably about 1 to 5 parts by weight can be added. Here, the alkyl (meth) acrylate is the same as that exemplified above, and the preferred copolymer is a copolymer having a melt flow rate of 0.1 to 50 g / 10 minutes at 190 ° C. and a load of 2160 g,
Particularly, it is about 1 to 30 g / 10 minutes. When such a copolymer is blended, more expensive ethylene
The same effect can be expected even if the amount of the alkyl (meth) acrylate / glycidyl (meth) acrylate terpolymer is reduced, but if the amount is too large, the rigidity of the composition decreases. Results.

The composition of the present invention may contain other thermoplastic resins and additives as long as the object of the present invention is not impaired. Examples of such additives include, for example,
Antioxidants, heat stabilizers, weather stability, light stabilizers, UV absorbers, lubricants, release agents, antistatic agents, plasticizers, flame retardants,
Examples include a foaming agent, a pigment, a dye, an inorganic filler, and a reinforcing fiber.

The composition of the present invention can be obtained by kneading each polymer component under melting conditions. When producing various molded articles from the composition of the present invention, after the kneading,
It is possible to adopt a method of molding as it is or a method of once pelletizing, re-melting and performing various moldings,
Generally, the latter method can produce a molded article having good physical properties with good quality stability. The molding temperature in this case is also
In general, a condition higher than the melting point of polyethylene terephthalate is employed, but a molded product having good physical properties can be obtained even when the temperature is higher than the melting point of polypropylene and lower than the melting point of polyethylene terephthalate.

[0022]

According to the present invention, it is possible to provide a composition excellent in moldability, impact resistance, low shrinkage, heat resistance and the like. Such a composition has the excellent features of polypropylene and can be used for the same applications as polypropylene. For example, it is molded into various molded products such as extrusion molding, injection molding, blow molding, press molding, vacuum molding, etc., and various household goods such as housing of various home appliances, industrial parts and tool boxes, dust boxes, racks, flower pots, etc. It can be used for applications.

Further, according to the formulation of the present invention, even from polyethylene terephthalate recycled from scrap,
Since a polypropylene composition having excellent physical properties can be obtained, the recycling of polyethylene terephthalate is effectively performed, which has a great effect on resource saving and improvement of environmental problems.

[0024]

The present invention will be described in detail with reference to the following examples. The types of various polymers used in Examples and Comparative Examples and methods for evaluating physical properties of the compositions are as follows.

1. Raw material polymer (1) Polypropylene

[Table 1]

(2) Polyethylene terephthalate

[Table 2]

(3) Ethylene copolymer

[Table 3] E • nBA • GMA: ethylene • n-butyl acrylate • glycidyl methacrylate copolymer E • EA: ethylene • ethyl acrylate copolymer E • GMA ： ethylene • glycidyl methacrylate copolymer

2. Physical property measurement method (1) Tensile characteristics: JIS K7113 JIS No. 1 test piece Tensile speed = 50 mm / min, interval between marked lines = 50 mm

(2) Flexural modulus: ASTM D790
Bending speed = 5mm / min

(3) Notched IZOD impact strength: JI
SK7115 Test piece thickness 1/8 inch (1/10 inch cutting notch) Measurement temperature 23 ° C, -20 ° C

(4) DuPont impact: test piece 2 mm thick flat plate, punch radius of impact 1/4 inch Measurement temperature 23 ° C, -20 ° C

(5) Mold shrinkage Test piece 2 mm thick flat plate Using a vernier caliper with an accuracy of 1/1000 mm, the resin flow direction (M
D) and the shrinkage in the direction perpendicular to the flow direction (TD) were determined.

[Embodiment 1] PP which is a block PP
(G704 manufactured by Grand Polymer Co., Ltd.) and polyethylene terephthalate PET (J13 manufactured by Mitsui Chemicals, Inc.)
5) was added in a ratio of 75:25 parts by weight, and 5 parts by weight of EC, which is an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer, was added to 100 parts by weight of the composition. In addition, dry blend,
The mixture was melt-kneaded at 270 ° C. using a 30 mm φ twin screw extruder (L / D = 32). Next, the obtained pellets were dried at 70 ° C. × 2 hr (in a nitrogen atmosphere) with a hot air drier, and then dried by Toshiba IS-
100E (clamping force 100 tons), cylinder temperature 27
Injection molding was performed at 0 ° C. and a mold temperature of 35 ° C. to prepare test pieces for measuring physical properties. Using these test pieces, the above-mentioned 2. The physical properties were evaluated under the following conditions. Table 4 shows the composition.
Table 5 shows the measurement results of physical properties of the composition.

[Comparative Example 1] No polyethylene terephthalate or ethylene copolymer was added, and block PP (PP
) Toshiba IS-100E alone (clamping force 100 tons)
Injection molding was performed at a cylinder temperature of 230 ° C. and a mold temperature of 35 ° C. to prepare a test piece for measuring physical properties, and the physical properties were evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5. This composition has a very high shrinkage during molding.

[Comparative Example 2] A test piece was prepared in the same manner as in Example 1 except that the ethylene copolymer was not added and the blend of only polypropylene and polyethylene terephthalate was used. Physical properties were evaluated in the same manner. The results are shown in Tables 4 and 5. Very low impact resistance.

[Comparative Example 3] EC ["Bond First 2C" (manufactured by Sumitomo Chemical Co., Ltd.)], which is an ethylene-glycidyl methacrylate copolymer, was replaced by 5 wt. A test piece of the composition was prepared in the same manner as in Example 1 except that a part was added, and the physical properties were evaluated. The results are shown in Tables 4 and 5. As a result, the impact resistance is inferior to that obtained by blending the terpolymer.

[Example 2] A test piece was prepared in the same manner as in Example 1 except that PET was replaced with recycled PET (a commercially available PET bottle was pulverized and then extruded into an extruder). Was prepared and physical properties were evaluated. The results are shown in Tables 4 and 5.

Example 3 In Example 2, the obtained pellets were dried by a hot air drier at 140 ° C. × 4 hours.
Physical properties were evaluated in the same manner as in Example 2 except that the condition of r was changed. The results are shown in Tables 4 and 5.

Example 4 Physical properties were evaluated in the same manner as in Example 2 except that 5 parts by weight of EC was added instead of EC as the ethylene copolymer. The results are shown in Tables 4 and 5.

[Comparative Example 4] A test piece was prepared in the same manner as in Example 2 after dry blending with the blend of PP and PET alone without adding the ethylene copolymer in Example 2.
Physical properties were evaluated. The results are shown in Tables 4 and 5. Very low impact resistance.

[Comparative Example 5] 5% by weight of EC ["Bond First 2C" (manufactured by Sumitomo Chemical Co., Ltd.)] which is an ethylene / glycidyl methacrylate copolymer instead of EC as the ethylene copolymer in Example 2 Physical properties were evaluated in the same manner as in Example 2 except that some parts were added. Table 4 shows the results
And 5. Compared to those containing a terpolymer,
Low impact resistance.

[Comparative Example 6] The physical properties were evaluated in the same manner as in Example 2 except that 5 parts by weight of EC was added instead of EC as the ethylene copolymer. The results are shown in Tables 4 and 5. Ethylene copolymer EC added
Is a terpolymer, but the impact resistance is lower than that of the terpolymer of the present invention because the content of n-butyl acrylate is small.

[Example 5] In Example 2, 3 parts by weight of EC was used instead of 5 parts by weight of EC as an ethylene copolymer, and EC which was an ethylene-ethyl acrylate copolymer was used.
Was evaluated in the same manner as in Example 2 except that 2 parts by weight was added. The results are shown in Tables 4 and 5. Physical properties almost equivalent to those obtained by adding 5 parts by weight of the terpolymer are obtained.

Comparative Example 7 The physical properties were evaluated in the same manner as in Example 5, except that only 5 parts by weight of EC was added as the ethylene copolymer. The results are shown in Tables 4 and 5. When only the ethylene / ethyl acrylate copolymer is blended, the impact strength is not sufficiently improved.

Comparative Example 8 The physical properties were evaluated in the same manner as in Example 2 except that 5 parts by weight of an ethylene-ethyl acrylate copolymer EC was added instead of EC as the ethylene copolymer. Done. The results are shown in Tables 4 and 5. As in Comparative Example 7, the impact resistance is low.

Example 6 The physical properties were evaluated in the same manner as in Example 2 except that the polypropylene was changed to J103 (PP) which is a homo PP. The results are shown in Tables 4 and 5.

[Comparative Example 9] Homo PP used in Example 6
To (PP), neither polyethylene terephthalate nor ethylene copolymer was added, and injection molding was performed independently at a cylinder temperature of 230 ° C. and a mold temperature of 35 ° C. using Toshiba IS-100E (clamping force: 100 tons), and physical properties were measured. A test piece was prepared and physical properties were evaluated in the same manner as in Example 6. The results are shown in Tables 4 and 5. Very low impact resistance and large molding shrinkage.

[Comparative Example 10] A test piece was prepared in the same manner as in Example 2 after dry blending with the blend of PP and PET alone without adding the ethylene copolymer in Example 6, and the same as in Example 1. And evaluated for physical properties. The results are shown in Tables 4 and 5. Very low impact resistance.

[0049]

[Table 4]

[0050]

[Table 5]

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Claims (3)

[Claims] An alkyl (meth) acrylate content of 15 to 40% by weight per 100 parts by weight of a polymer component comprising 60 to 95 parts by weight of polypropylene and 40 to 5 parts by weight of polyethylene terephthalate, (meth) acrylic acid A polypropylene composition comprising 1 to 20 parts by weight of an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer having a glycidyl content of 1 to 15% by weight. 2. An alkyl (meth) acrylate content of 15 to 40% by weight per 100 parts by weight of a polymer component comprising 60 to 95 parts by weight of polypropylene and 40 to 5 parts by weight of polyethylene terephthalate, and (meth) acrylic acid 1-20 parts by weight of an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer having a glycidyl content of 1 to 15% by weight and ethylene having an alkyl (meth) acrylate content of 15 to 40% by weight · (Meth) acrylic acid alkyl ester copolymer 1
A polypropylene composition containing 10 parts by weight. 3. The polypropylene composition according to claim 1, wherein the polyethylene terephthalate is recycled polyethylene terephthalate.