JPH05140382A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful as a material for packaging vessels because of its excellent heat resistance, stiffness, humid resistance and surface properties by mixing a specific resin composition with a modified polypropylene polymer. CONSTITUTION:(A) A polypropylene polymer of preferably 5 to 95 pts.wt., is mixed with (B) a polystyrene polymer of preferably 95 to 5 pts.wt. and the resultant mixture of 100 pts.wt. are combined with (C) 1 to 100 pts.wt. of a modified PP polymer which is prepared by reacting, under melt-kneading, of a PP polymer bearing a reactive group selected from carboxyl, hydroxyl, epoxy, amino and oxazoline together with a PS polymer bearing a reactive group selected from the groups which can do esterification reaction with said PP polymer to give the objective composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel and useful thermoplastic resin composition. More specifically, the present invention provides
A polypropylene-based polymer, a polystyrene-based polymer and a specific modified propylene-based polymer, which have, among others, excellent heat distortion resistance, impact resistance, rigidity and moisture resistance (moisture resistance), and in addition, The present invention relates to a thermoplastic resin composition that also has improved moldability.

[0002]

2. Description of the Related Art Polypropylene has a low cost per se and is excellent in mechanical strength, heat resistance, oil resistance and electrical properties, and therefore, it is available in various types as films, fibers or molded products. Is widely used for

However, such polypropylene has the following problems in terms of rigidity, sheet workability and surface characteristics.
It is inferior to other vinyl polymers, especially polystyrene.

For example, in the field of packaging containers, polypropylene is inevitably low in rigidity as compared with polystyrene, so that it is difficult to process a sheet.

On the other hand, in terms of heat resistance, oil resistance and moisture resistance, there are advantages such as being superior to polystyrene. Therefore, if a molding material that has the advantages of polypropylene and the advantages of polystyrene in a well-balanced manner can be made, it can be used again in application fields where it was impossible to use in the past. Is expected to be.

However, polypropylene and polystyrene are incompatible with each other, and if they are simply blended, the interfacial adhesion between these two resins is poor.
Dispersion of the polystyrene part becomes insufficient, and eventually phase separation occurs, resulting in unsatisfactory mechanical properties such as rigidity and impact resistance of the molded product.
It means that it is not practical.

In order to improve such a surface, for example, a so-called rubber substance such as a styrene-butadiene-block copolymer or a hydrogenated product of the block copolymer is used as a compatibilizing agent for both resins. Although there is a method of adding it, the dispersion of the styrenic polymer in the obtained molded product is slightly improved, and the impact property is somewhat improved, but the rigidity is significantly reduced. The reality is that it cannot be put to practical use again.

In addition to these rubber substances, Japanese Patent Laid-Open No. 61-
No. 285209 discloses a copolymer of a vinyl ester-based monomer having a peroxide group and a styrene-based monomer,
A method has been disclosed in which a so-called modified polypropylene, which is obtained by a melt-kneading reaction with a propylene-based polymer, is added as a compatibilizing agent.

However, the vinyl ester monomer having such a special peroxide group is not expensive as it is, and it is directly mixed with the styrene monomer.
Since there are problems such as radical copolymerization being difficult,
Although it is complicated in the polymerization process, the fact is that it is still not practical as a compatibilizing agent for general-purpose polymers.

[0010]

As described above, the resin composition of the propylene polymer and the styrene polymer obtained by the conventional method is practically satisfactory in terms of polymer performance or production. It wasn't like that.

It can be said that this is due to insufficient dispersion of polystyrene in the propylene polymer. In order to sufficiently disperse such polystyrene, the presence of a block / graft copolymer of a propylene-based polymer having a compatibilizing action and polystyrene is desirable, but the crystallinity of polypropylene is also high. Due to that, the melting point becomes high, and because it does not dissolve in the styrene-based monomer,
It is considered that it is difficult to obtain a graft polymer by the above method.

Therefore, as a result of intensive investigations by the present inventors to solve the above-mentioned drawbacks of the conventional method, a propylene-based polymer having a reactive polar group (reactive group) such as a carboxyl group. And a styrene-based polymer having a reactive group such as an epoxy group, obtained by melt-kneading reaction, a so-called modified propylene-based polymer,
By adding it to a resin composition of a propylene-based polymer and a styrene-based polymer, a highly useful thermoplastic resin composition having excellent rigidity, impact resistance and moisture permeability can be obtained. After finding out the above, the present invention has been completed here.

[0013]

[Means for Solving the Problems] That is, the present invention basically relates to a resin composition comprising a polypropylene-based polymer (A) and a polystyrene-based polymer (B), and a specific modified propylene. A polymer (C), for example, by adding a specific modified propylene polymer (C) obtained by the following production method,
It is an object of the present invention to provide a thermoplastic resin composition having excellent rigidity, impact resistance, moisture resistance (moisture resistance) and the like, which is extremely highly practical.

That is, a propylene-based polymer having a reactive group selected from the group consisting of a carboxyl group, a hydroxyl group, an epoxy group, an amino group and an oxazoline group, and an esterification reaction with the propylene-based polymer, the above It refers to a specific modified propylene-based polymer obtained by melt-kneading a styrene-based polymer having a reactive group selected from the following group.

[0015]

[Structure] In the present invention, only the typical polypropylene resin (A) used in the present invention will be exemplified. Isotactic polypropylene, propylene-ethylene / random copolymer or propylene- Preferred are propylene homopolymers or copolymers such as ethylene / block copolymers, and various modified products such as oxidation / chlorination of these polymers. Various combinations of are possible.

Among these, particularly desirable ones are
Examples include isotactic polypropylene and propylene-ethylene copolymer. In addition, polystyrenes, acrylonitrile-butadiene-styrene copolymers (ABS resins), acrylonitrile-styrene copolymers can be cited as specific examples of the polystyrene-based resins (B) used in the present invention. , Styrene-methylmethacrylate copolymer, rubber-containing polystyrene and the like are preferable, and various combinations thereof are possible.

Of these, polystyrene, ABS resin, rubber-containing polystyrene and the like are particularly preferable. Furthermore, only by exemplifying the particularly representative modified propylene polymer used in the present invention, a reaction selected from the group consisting of a carboxyl group, a hydroxyl group, an epoxy group, an amino group and an oxazoline group. A propylene-based polymer having a reactive group and a styrene-based polymer having a reactive group selected from each of the above groups capable of undergoing an esterification reaction with the propylene-based polymer are obtained by melt-kneading reaction. Something like that.

The propylene-based polymer having various reactive groups as described above, which is used for the preparation of the modified propylene-based polymer, includes propylene homopolymers and propylene-based polymers. Copolymers with olefins or ethylenically unsaturated monomers, in particular any of which is a copolymer with 75% by weight or more of propylene, specifically, Isotactic polypropylene, crystalline propylene-ethylene copolymer, crystalline propylene-butene copolymer, and the like are each mixed with an unsaturated carboxylic acid, an unsaturated epoxy monomer, an unsaturated hydroxy monomer, and an unsaturated amino monomer. Monomers and monomers having at least one reactive group selected from the group consisting of monomers and unsaturated oxazoline monomers. Pyrene-based polymer, and the like.

Here, only representative examples of the above-mentioned unsaturated carboxylic acid are acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid and the like.

Specific examples of the above unsaturated epoxy monomer include glycidyl acrylate, glycidyl methacrylate, itaconic acid diglycidyl ester, and 3,4-epoxy-1-butene.

As the unsaturated hydroxy monomer, only typical ones are exemplified, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.
For example, hydroxypropyl acrylate or 2-hydroxybutyl methacrylate.

Specific examples of the above unsaturated amino monomers include dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate.

As the unsaturated oxazoline monomers mentioned above, only typical ones are exemplified, 2-vinyl-2-oxazoline and 2-vinyl-4-methyl-2.
-Oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-oxazoline and the like.

Above all, various carboxyl group-containing propylene-based polymers such as acrylic acid and maleic acid are preferable in terms of reactivity and ease of handling. The amount of the reactive functional group-containing monomer contained in the propylene-based polymer is 1 to 20% by weight, preferably 2 to 10% by weight.

It goes without saying that the binding mode of the propylene polymer containing a reactive functional group may be any of a random copolymer, a block copolymer and a graft polymer.

Further, only specific examples of the styrene-based polymer having a reactive group used for the preparation of the modified propylene-based polymer will be given. Polystyrene, acrylonitrile-styrene copolymer, Acrylonitrile-butadiene-styrene copolymer or styrene-methacrylate copolymer, unsaturated carboxylic acid, unsaturated epoxy monomer, unsaturated hydroxy monomer,
Examples thereof include a propylene-based polymer in a form in which an unsaturated amino monomer or an unsaturated oxazoline monomer is subjected to an addition reaction.

Specific examples of such unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, and the like, as described above.

Similarly, if only representative examples of the above unsaturated epoxy monomer are given, glycidyl acrylate, glycidyl methacrylate, itaconic acid diglycidyl ester or 3,4-epoxy-
1-butene and the like.

If only representative examples of the above-mentioned unsaturated hydroxy monomer are given, similarly, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2- For example, hydroxypropyl acrylate or 2-hydroxybutyl methacrylate.

As the unsaturated amino monomers mentioned above, only typical ones are exemplified by dimethylaminoethyl methacrylate or diethylaminoethyl methacrylate as described above.

If only typical examples of the above unsaturated oxazoline monomer are given, similarly, as described above, 2-vinyl-2-oxazoline, 2
-Vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline or 2-isopropenyl-4-oxazoline.

Above all, the use of an epoxy group-containing styrene-based polymer such as glycidyl acrylate or glycidyl methacrylate is preferable from the viewpoints of reactivity and easy handling.

The amount of the reactive functional group-containing monomer contained in the styrene polymer is 1 to 20% by weight, preferably 2 to 10% by weight. As a matter of course, the coupling mode of the styrene polymer containing a reactive functional group may be a random copolymer, a block copolymer or a graft polymer.

The polymerizing reaction for obtaining the modified propylene polymer can be carried out using a closed container such as Banbury or a continuous kneader such as an extruder. Above all,
The extruder is more preferable when considering so-called industrial production such as granulation, and the twin-screw extruder is more preferable in terms of supply of reactants and control of polymerization time. This is advantageous because it can be performed easily.

As a preferred preparation method, a powdery or pelletized propylene-based polymer and a styrene-based polymer are fed to an extruder and pressurized to 130 to 25.
It is like heating in a temperature range of about 0 ° C., melt-kneading under conditions where a polymerizing reaction occurs, and then discharging from a die.

The modified propylene-based polymer thus obtained may be directly subjected to a pelletizer and taken out, and subsequently, a mixture of a polypropylene-based polymer and a polystyrene-based polymer may be used together, or each may be used as a polypropylene. It is needless to say that the system- or polystyrene-based polymer may be melt-kneaded separately to form a molded product, or may be taken out as a pellet.

When obtaining the modified propylene-based polymer,
It goes without saying that a catalyst, a stabilizer or the like may be added to accelerate the polymerizing reaction or to prevent the decomposition of the polymer itself.

The thermoplastic resin composition of the present invention essentially comprises a polypropylene polymer (A), a polystyrene polymer (B), and a modified propylene polymer (C). However, the mixing ratio of the three components (A), (B) and (C) is 5 to 95 parts by weight, preferably 20 to 85 parts by weight of the component (A).
95-5 parts by weight of component (B), preferably 80-15
Parts by weight; 1 to 100 parts by weight, preferably 5 to 30 parts by weight, relative to 100 parts by weight of the total amount of these components (A) and (B), (C) component. The proportion is appropriate.

In addition to these essential components, the composition of the present invention may contain further additional components within the range not departing from the object of the present invention or so as not to impair the effects of the present invention. It can be added in a range.

As only such typical additional components, only typical ones are exemplified. Other thermoplastic resins, rubbers, inorganic fillers, pigments, various stabilizers (antioxidants, etc.). , Light stabilizers, antistatic agents, antiblocking agents and lubricants).

The thermoplastic resin composition of the present invention can be obtained by dry-blending the components listed above and directly molding it, but generally, it is generally prepared in advance by using a roll, a Banbury mixer or an extruder. The composition is melt-mixed with various kneading machines to form a composition, and then subjected to molding.

For such molding, any method such as injection molding, blow molding or extrusion molding can be adopted.
The composition of the present invention is a thermoplastic resin excellent in heat resistance, rigidity, impact resistance, moisture resistance (moisture resistance) and surface property, among others.

The thermoplastic resin composition of the present invention thus obtained can be applied to various packaging material-related fields such as packaging container materials, and as described above, the composition of the present invention can be used. Due to its high practicability, the field of application will be further expanded.

[0044]

EXAMPLES Next, the present invention will be described more specifically with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, all parts and% are based on weight unless otherwise specified.

Reference Example 1 (Synthesis Example of Epoxy-Modified Polystyrene Used in Modified Propylene Polymer) In a separable flask with a reflux apparatus having an internal volume of 5 liters, 1,868 parts of pure water and a suspension were added. 33 parts of calcium phosphate as a turbidity agent and 0.2 part of sodium lauryl sulfate were added to form an aqueous medium (suspension system), to which "Perbutyl O" as a polymerization initiator [NOF 20 parts of [Products] was dissolved in 950 parts of styrene, 50 parts of glycidyl methacrylate and 2 parts of lauryl mercaptan and added to the above suspension-based aqueous medium.

Then, this aqueous suspension was heated to 80 ° C. under a nitrogen atmosphere and stirred for 7 hours to complete the polymerization. Thereafter, the product obtained here was washed with dilute hydrochloric acid water and the like, and then dried.

Reference Example 2 (Preparation Example of Modified Propylene Polymer) A 20 mm single-screw extruder manufactured by Brabender of Germany was used.
The barrel temperature was set to 200 ° C. (however, the temperature of the feeder section was 180 ° C.) and the die temperature was set to 210 ° C.

A mixture was prepared by mixing 100 parts of "Admer QF540" [maleic acid-modified polypropylene manufactured by Mitsui Petrochemical Industry Co., Ltd.] with 100 parts of the epoxy-modified polystyrene obtained in Reference Example 1. , Feed the extruder and extrude at a speed of 20 revolutions per minute, then
Through the pelletizer, 190 parts of product pellets were obtained.

Example 1 "Union Polymer RB110" [polypropylene manufactured by Tokuyama Soda Co., Ltd.] and "Dick Styrene CR35"
00 ”[polystyrene manufactured by Dainippon Ink and Chemicals, Inc.] and the modified propylene-based polymer obtained in Reference Example 2 in the proportions shown in Table 1 to obtain the data from Toshiba Corporation.
"IS50AM injection molding machine" manufactured by
A test piece was prepared under the condition of 0 ° C.

Various physical properties of this test piece were evaluated. The results are shown together in the same table. As is clear from the table, there is no delamination in this test piece, and the other various physical properties also exceed the standard values as a packaging material, and are suitable as packaging materials. It was confirmed that there is.

Comparative Example 1 A test piece was prepared and various physical properties were evaluated in the same manner as in Example 1 except that the modified propylene polymer was not used. The results are summarized in Table 1.

As is clear from the table, this test piece had delamination, and the impact strength did not reach the standard value, and it was confirmed that the test piece was unsuitable as a packaging material. Was done.

Comparative Example 2 Specimens were prepared in the same manner as in Example 1 except that the use of the modified propylene-based polymer was omitted and that only polypropylene was used. Was evaluated. The results are summarized in the first
Shown in the table.

As is apparent from the table, this test piece had no delamination, but the bending strength did not reach the standard value, and it was confirmed that the test piece was unsuitable as a packaging material. Was done.

Comparative Example 3 Specimens were prepared in the same manner as in Example 1 except that the use of the modified propylene-based polymer was omitted and that only polystyrene was used. Was evaluated. The results are summarized in Table 1.

As is apparent from the table, the test piece has no delamination, but the impact strength and the moisture permeability do not reach the respective standard values, and as a packaging material,
It was confirmed to be inappropriate.

Comparative Example 4 A sample was prepared in the same manner as in Example 1 except that the same amount of “Admer QF540” was used instead of the modified propylene polymer, and various physical properties were measured. An evaluation was made. The results are summarized in Table 1.

As is clear from the table, delamination was observed in this test piece, and the impact strength did not reach the standard value, and it was found to be unsuitable as a packaging material. Was confirmed.

[0059]

[Table 1]

[0060]

[Footnote in Table 1] "Modified PP" ... Modified polypropylene "Modified PP" ... Modified polypropylene Layered peeling ... Wiping the molding surface with toluene to visually determine the presence or absence of layered peeling. Thermal deformability ... JIS K- According to 7202, measure the Vicat temperature under a load of 1 kg; unit =
C. Bending strength: measured according to JIS K-7203; unit =
kg / cm2 Impact strength: measured according to ASTM D-256; unit =
kg / cm Moisture permeability… 150 micron (μ
m) using a sheet having a thickness of
Measurement according to: Unit = g / m 2, 24 hrs.

The necessary standards for the above-mentioned measured physical properties of the packaging material are as follows. Thermal deformability: 125 ° C or more Bending strength: 500 kg / cm 2 or more Impact strength: 4.8 kg / cm or more Moisture permeability: 10 g / m 2, 24 hrs. Less than

Example 2 When preparing a modified propylene-based polymer, the same amount of "Polybond" (acrylic acid-modified polypropylene manufactured by Reichhold, USA) was used instead of 100 parts of "Admer QF540". Except changed to
In the same manner as in Example 1, 195 parts of product pellets were obtained.

Thereafter, in the same manner as in Example 1, test pieces were prepared from the above-mentioned modified propylene polymer and polypropylene and polystyrene at the ratios shown in Table 2, and the physical properties were evaluated. went. The results are summarized as
Shown in the same table.

As is clear from the table, this test piece has no delamination, and all other physical properties exceed the standard values as a packaging material, and are suitable as a packaging material. It was confirmed to be a good one.

Example 3 In preparing a modified propylene-based polymer, instead of 100 parts of "Admer QF540", the same amount of "Tufmer XR106L" [maleic acid-modified propylene olefin manufactured by Mitsui Petrochemical Co., Ltd.] was used. Copolymer] was used in the same manner as in Example 1 except that 195 was used.
Some product pellets were obtained.

Thereafter, in the same manner as in Example 1, a sample was prepared from the above-mentioned modified propylene polymer in the proportions shown in Table 2 with polypropylene and polystyrene, and then the physical properties were An evaluation was made. The results are shown together in the same table.

As is clear from the table, this test piece has no delamination, and the various other physical properties also exceed the standard values as a packaging material, and are suitable as a packaging material. It was confirmed to be a good one.

Example 4 In preparing a modified propylene-based polymer, Reference Example 1
Same as Example 1 except that the same amount of "RPS-1005" [oxazoline-modified polystyrene manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.] was used instead of 100 parts of the epoxy-modified polystyrene obtained in 1. To give 195 parts of product pellets.

Thereafter, in the same manner as in Example 1, test pieces were prepared from the above-mentioned modified propylene polymer and polypropylene and polystyrene at the ratios shown in Table 2, and the physical properties were evaluated. went. The results are summarized as
Shown in the same table.

As is clear from the table, this test piece has no delamination, and all other physical properties exceed the standard values as a packaging material, and are suitable as a packaging material. It was confirmed to be a good one.

[0071]

[Table 2]

[0072]

INDUSTRIAL APPLICABILITY According to the present invention, a propylene polymer having a reactive group typified by a carboxyl group and a styrene polymer having a reactive group typified by an epoxy group are melt-kneaded. Obtained by the specific modified propylene-based polymer, a polypropylene-based polymer, and a polystyrene-based polymer, a thermoplastic resin composition, in particular, also in mechanical strength,
To provide a thermoplastic molding material which is also excellent in moldability, and which is particularly useful as a packaging container material and which has excellent balance in rigidity, heat deformability and moisture resistance (moisture permeability). Can be done.

Claims (4)

[Claims] 1. A resin composition comprising a polypropylene polymer (A) and a polystyrene polymer (B),
A thermoplastic resin composition comprising a modified polypropylene polymer (C) obtained by melt-kneading a reactive group-containing polypropylene polymer and a reactive group-containing polystyrene polymer. 2. A polypropylene-based polymer (A) 5-9.
Melt of the reactive group-containing polypropylene polymer and the reactive group-containing polystyrene polymer with respect to 100 parts by weight of the resin composition consisting of 5 parts by weight and 95 to 5 parts by weight of the polystyrene-based polymer (B). A thermoplastic resin composition, characterized in that 1 to 100 parts by weight of a modified polypropylene polymer (C) by kneading is added. 3. The polypropylene-based polymer (C), wherein the modified polypropylene-based polymer (C) has a reactive group selected from the group consisting of a carboxyl group, a hydroxyl group, an epoxy group, an amino group and an oxazoline group. The polypropylene-based polymer and the polystyrene-based polymer having a reactive group selected from the above-mentioned reactive group group capable of undergoing an esterification reaction are obtained by melt-kneading reaction, and are obtained. Thermoplastic resin composition. 4. The modified polypropylene polymer (C) is obtained by melt-kneading a polypropylene polymer having a reactive group which is a carboxyl group and a polystyrene polymer having a reactive group which is an epoxy group. The thermoplastic resin composition according to claim 1 or 2, which is obtained.