JP2003105143A - Resin composition and laminate - Google Patents

Resin composition and laminate

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Publication number
JP2003105143A
JP2003105143A JP2001296697A JP2001296697A JP2003105143A JP 2003105143 A JP2003105143 A JP 2003105143A JP 2001296697 A JP2001296697 A JP 2001296697A JP 2001296697 A JP2001296697 A JP 2001296697A JP 2003105143 A JP2003105143 A JP 2003105143A
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JP
Japan
Prior art keywords
resin
polypropylene
polystyrene
laminate
resin composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2001296697A
Other languages
Japanese (ja)
Inventor
Yoshisue Ohashi
Masayoshi Suzuta
美季 大橋
昌由 鈴田
Original Assignee
Toppan Printing Co Ltd
凸版印刷株式会社
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Filing date
Publication date
Application filed by Toppan Printing Co Ltd, 凸版印刷株式会社 filed Critical Toppan Printing Co Ltd
Priority to JP2001296697A priority Critical patent/JP2003105143A/en
Publication of JP2003105143A publication Critical patent/JP2003105143A/en
Pending legal-status Critical Current

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Abstract

(57) [Problem] To provide a resin composition and a laminate having an easy peel property based on a polypropylene resin. The melt index is 0.1 to 50 g / 1.
Polystyrene (resin B) is blended with 1 to 50 wt% of a long-chain branched polypropylene homopolymer or block polymer (resin A) within a range of 0 min, and 100 parts by weight of resin A + resin B is added to polypropylene resin. In a resin composition containing 0.01 to 20 parts by weight of a graft polymer (resin C) on which a polystyrene resin is grafted, the resin C has the following characteristics. (1) Polystyrene in resin C is 1 to 50% by weight of polystyrene based on polypropylene. (2) The resin C utilizes a reactive group introduced into a polystyrene terminal or main chain,
Branched or pendant grafted structure.
(3) The basic skeleton of polypropylene resin of resin C is resin A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition in which an adherend has an easy peel property with respect to a polypropylene resin and a laminate thereof, and more specifically, not only has resistance to boil and retort, and The present invention relates to a resin composition capable of imparting high-speed processing suitability of a polypropylene resin composition, which has been difficult in the past, and a laminate thereof.

[0002]

2. Description of the Related Art In the field of food packaging, packaging forms in which contents such as instant noodles, jellies and yogurts are filled in cups have been increasing. Recently, HM
The flow of R (home meal replacement) has become stronger, and along with this, the number of trays that can be frozen and distributed and have heat resistance such as microwave ovens is gradually increasing. As a typical example of these containers, various thermoplastic resins such as polyethylene, polystyrene, expanded polystyrene, polypropylene, and polyester are generally manufactured by using a manufacturing method such as injection molding or vacuum compression molding. In many cases, polypropylene resin is used to meet the requirements of sterilization and boil / retort sterilization. Recently, in consideration of environmental problems, paper trays in which paper and polypropylene film or polyester film are combined have been used.

In order to meet the demands of the market as described above, the side of the lid material is required to have a function of having good adhesiveness and adhesiveness to various containers and having an easy opening property at the time of opening. It's coming. In this way, in order to meet the contradictory requirements of having easy-opening property while having adhesiveness, sealant designs having various easy-opening properties have come to be used. Delamination type sealant has come into the market.

The cohesive exfoliation type sealant uses a resin composition composed of an incompatible polymer blend as a sealant layer and reduces the interfacial adhesion between the base resin and the blended resin to reduce the cohesive force of the sealant layer. is there. Such a cohesive peeling type sealant is often used as a sealant for a lid material for the above-mentioned container because it has a small change in peel strength with respect to the sealing pressure and can impart stable peeling property. .

As a method of designing such a cohesive exfoliation type sealant, first of all, selection of a base resin in consideration of processability is mentioned, and low density polyethylene is preferably used in view of processability. However, since the base resin is selected in consideration of workability, the following points are mentioned as problems.

First of all, since low density polyethylene is used as the base resin, it is inferior in heat resistance as a sealant especially for polypropylene containers, while the container side has microwave oven compatibility and boil / retort resistance. It is necessary to improve the heat resistance of the lid sealant.

Secondly, in order to impart a sealing property to the polypropylene resin as the adherend, it is necessary to mix the polypropylene resin with the low density polyethylene which is the base resin of the sealant. However, since the polypropylene resin blended in this sealant layer is a small component when viewed as a whole sealant, there is concern about the sealing property (adhesion) with the adherend, and in some cases the polypropylene dispersion state depending on the processing conditions. Depending on the situation, it may not be possible to obtain the optimum sealing property.

Thirdly, in order to function as cohesive exfoliation, it is necessary to mix the above-mentioned polyolefin resin such as polystyrene and an incompatible resin, and it is necessary to comprise at least a three-component resin composition. Further, in order to impart further functionality to the sealant, it is necessary to mix another resin, which may result in a multi-component blend. In this multi-component polymer blend, the balance of the compounding ratio of each component becomes important, and the quality control of the sealant may become strict.

Fourthly, some of the cohesive exfoliation sealants currently on the market have a special polymer alloy (polymerization).
The technology is put to good use and it is very expensive. Also, adding more functionality may add cost and increase costs. Since the above-mentioned lid material has a low unit price per sheet, it is the current situation that it is desired to reduce the material cost as much as possible, but in reality, pursuing functionality results in an expensive lid material.

As described above, the cohesive peeling type easy peel sealant using polypropylene as an adherend has many improvements left. It is desirable to use a polypropylene resin as the base resin in order to provide stable sealing properties and heat resistance to the adherend and to simplify the type of resin to be mixed as much as possible. Since it is a resin having a small upper melt tension, it is presently inferior in workability. Therefore, a polypropylene resin is used as a base polymer to improve the workability, the physical properties for sealing the adherend, and the heat resistance, and a sealant having an easy peel property without using a special alloying technique is desired. ing.

Considering the container as a composite paper container in which paper and polypropylene are composited, the composite paper container is
When a two-dimensional one is molded into a three-dimensional one in order to break a laminated body of paper and polypropylene resin and form it into a container, an overlapping part (step) of the paper
Will inevitably occur. When sealing with a container having such a stepped portion as a lid material, it is necessary to add adhesiveness to such a stepped portion, but with the current sealant, this adhesiveness has not been improved. .

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition and a laminated body having a polypropylene resin as a base and having an easy peeling property in view of the above situation.

[0013]

The present invention has been devised to overcome the above-mentioned problems, and the invention according to claim 1 has a melt index in ASTM D1280 of 0.1 to 50 g / 10 min. Long-chain branched polypropylene homopolymer or long-chain branched polypropylene block polymer (resin A) 50 to 99 wt
% Of polystyrene (resin B), and 0.01 to 100 parts by weight of the resin A + resin B is added to the graft polymer (resin C) obtained by grafting polystyrene resin on polypropylene resin. In a resin composition containing 20 parts by weight, the structure of the graft polymer (resin C) has the following characteristics. (1) The weight ratio of polypropylene to polystyrene in Resin C is 50 to 99 wt% of polypropylene and 1 to 50 wt% of polystyrene. (2) The resin C has a structure in which a polypropylene group is grafted in a branched or pendant form in the polypropylene main chain by utilizing a reactive group introduced at the polystyrene end or in the polystyrene main chain. (3) The basic skeleton of the polypropylene resin forming the resin C is the resin A.

The invention according to claim 2 has a temperature of 260 to 30.
At 0 ° C., the magnitude relationship between the melt viscosity η (resin A) of the resin A and the melt viscosity η (resin B) of the resin B in the shear rate range of 10 1 to 10 2 (1 / sec) is η (resin A). The resin composition according to claim 1, having a relationship of ≤ η (resin B).

A third aspect of the present invention is a laminate characterized by using the resin composition according to the first or second aspect as a sealant layer in a thickness range of 1 to 30 μm.

According to a fourth aspect of the invention, the dispersion size of the polystyrene resin (resin B) dispersed in the long-chain branched polypropylene resin (resin A), which is the base resin of the sealant layer, is on the order of μm, and the sealant is used. The laminated body according to claim 3, characterized in that, when observed from the thickness direction, the polystyrene dispersion state is an elliptic to acicular state stretched in the MD direction.

According to a fifth aspect of the present invention, when the sealants are sealed side by side, or when the polypropylene resin and the laminate are sealed, peeling of the sealing portion is performed by cohesive failure of the sealant layer, and the peeling occurs. The strength is in a range of 5 to 20 N / 15 mm, and the laminated body according to claim 3 or 4.

The invention according to claim 6 is characterized in that the laminate is used as a lid material having an easy peel property for a polypropylene resin container or a composite container made of paper and polypropylene resin. The laminated body according to any one of 5 above.

The invention according to claim 7 is the laminate according to any one of claims 3 to 5, characterized in that the laminate is used as a soft packaging material having an easy peel property.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The resin composition and the laminate of the present invention are designed in consideration of the above-mentioned polypropylene processability. First of all, considering the film forming property, especially high-speed processability such as extrusion lamination, the ASTM (American Society for
Testing Materials, American Society for Testing Materials) D12
Melt index (MI) at 80 is 0.1 to 5
0 g / 10 min, particularly preferably 5-40 g / 10 m
in, and more preferably, a polypropylene resin (resin A) in the range of 10 to 30 g / 10 min. Further, while considering the processability, the sealant base resin is easily softened by the heat at the time of sealing so as to add the step difference to the composite paper container described above. It is preferable to use the above resin. Furthermore, if the MI in the above range is satisfied, not only the composite paper container but also a general-purpose polypropylene container can be applied.

Further, compared with resins having excellent processability such as low-density polyethylene, polypropylene resins do not have long-chain branching in the polymer structure, so that the melt tension is small and the viscosity characteristics during melting are greatly different. Further, in general, when a polypropylene resin is mixed with an incompatible resin such as high-density polyethylene or polystyrene, problems in processing such as melt fracture and draw resonance easily occur due to its viscosity characteristics. In that sense, as the polypropylene resin (resin A) selected as the base polymer, it is preferable to use a resin having a high melt tension within the above melt index range. As such a polypropylene resin, a long-chain branched polypropylene resin can be mentioned, and as the manufacturing method thereof, those obtained by modification with EB (electron beam), peroxide, various crosslinking agents, etc. can be used. Is. As such a long-chain branched polypropylene resin, there are types such as homopolymers and block polymers, but there is no particular limitation, and it is possible to use properly depending on the required requirements such as heat resistance and impact resistance. Is.

The definition of long-chain branched polypropylene is in accordance with the contents described in Japanese Patent Publication No. 7-45551, which is dissolved in decahydronaphthalene to give 135
Intrinsic viscosity measured at 0 C of at least 0.8 dl /
g, and the branching index is less than 1, preferably 0.2 to
It has a strain hardening elongation viscosity of 0.4. As the long-chain branched polypropylene, it is preferable to use a resin satisfying the above-mentioned content, but it is not particularly limited to the above-mentioned content.

Examples of the blend phase (resin B) added to the polypropylene resin (resin A) serving as the base resin to exhibit the easy peeling property include resins that are incompatible with the polypropylene resin. For example, high density polyethylene, medium density polyethylene, low density polyethylene, ethylene-α olefin copolymer, ethylene-α, β unsaturated carboxylic acid, ion-crosslinked product of ethylene-α, β unsaturated carboxylic acid, ethylene -Esterification products of α, β unsaturated carboxylic acid, polystyrene resin,
There are various types such as polyester resin and polyamide resin,
Considering the stability of the peel behavior, polystyrene resin is preferable.

The blending ratio in the sense of imparting easy peelability is such that the long-chain branched polypropylene resin (resin A) is 50 to 99 wt% and the polystyrene resin (resin B) is 1 to 50 wt%. Is preferred. The blend ratio is effective for controlling the peel strength, and it is possible to set the peel strength strong by decreasing the polystyrene content, and conversely, set the peel strength weak by increasing the blending ratio.

In a simple incompatible blend of the resin A and the resin B, the interfacial adhesion strength between the resin A and the resin B is weak. Therefore, by mixing the resin B in the resin A, the cohesive force of the resin A is increased. Although it is possible to lower the adhesiveness and provide easy peeling property, if the interfacial adhesive strength is weak, there arises a problem that the edge portion of the sealing surface due to heat sealing cannot be properly broken during peeling. This fluffing problem not only impairs the peeled appearance, but also has a problem in terms of quality stability. In that sense, in order to improve the interfacial adhesion between the resin A and the resin B, 100 parts by weight of the above resin composition is used as the third component, which is a graft polymer (resin C) obtained by graft-polymerizing polystyrene with polypropylene resin. On the other hand, it is necessary to add 0.01 to 20 parts by weight as a compatibilizer.

The resin C to be blended with the above resin composition is roughly classified into the following types. (1) Grafted styrene monomer onto polypropylene (2) Grafted polystyrene in the polypropylene main chain by introducing a reactive monomer at the polystyrene end (3) Reactive monomer What is introduced into a polystyrene skeleton and is grafted into a polypropylene main chain in a pendant form The graft polymer (resin C) usable in the present invention is not limited to the above-mentioned structure, and any skeleton can be used. For the following reasons (2) or (3)
It is preferable to use any one of them or a mixture thereof.

For details of the graft polymer having the structure of (2) or (3) above, see Japanese Patent Publication No. 6-
It can be obtained by using a graft polymerization method typified by Japanese Patent Publication No. 51767.

The advantages of using such a graft polymer are as follows. In the case of the above-mentioned graft polymer (1), it is effective as a compatibilizing agent for the resin A and the resin B as in the cases (2) and (3), and it is necessary to improve the interfacial adhesion strength between the resin A and the resin B. Although it is possible to improve the interfacial adhesive strength, while it is effective for fuzzing,
The peel strength is remarkably improved and the easy peeling property is lowered. Therefore, not only the blending ratio of the resin B but also the blending ratio of the resin C significantly affects the peel strength, which makes quality control very difficult and, at the same time, the blending ratio for exhibiting the function is narrow. Become.

On the other hand, in the case of the graft polymer as described in the above (2) or (3), polypropylene is grafted with polystyrene in the graft polymer because of the content of the production method described in the above patent. In addition to the polymer having the structure described above, the polystyrene homopolymer is inevitably contained. The polystyrene homopolymer inevitably contained in this graft polymer (resin C) can fulfill the same function as that of resin B, and even if the compounding ratio of resin C is increased, the peel strength is greatly affected. That is, the addition of resin C improves the interfacial adhesion strength between resin A and resin B, thereby increasing the peel strength, but the polystyrene homopolymer originally contained in resin C fulfills the function of resin B ( By increasing the proportion of the resin that fulfills the function of the resin B), the peel strength decreases. By increasing (decreasing) the peel strength, the stability of the peel strength is provided even if the resin C is added. It is possible. In addition, the sensual peel feeling is remarkably improved, and it is possible to open the container smoothly.

The weight ratio of polypropylene to polystyrene in the above-mentioned graft polymer (resin C) is 50 to 99 wt% of polypropylene and 1 to 5 of polystyrene.
It is preferably 0 wt%. When the polystyrene content is 1% or less, the interfacial adhesion strength between the resin A and the resin B is adjusted, so that the blending amount of the graft polymer is increased and the content of the polystyrene homopolymer contained in the resin C is also reduced. The stability of peel strength cannot be obtained depending on the addition amount of. Further, when polystyrene is 50 wt% or more, the effect as a compatibilizing agent of the resin A and the resin B can be obtained, but grafting of polystyrene more than necessary means introducing more homopolymer than necessary, and peeling is performed. It also affects the stability of strength. In that sense, polystyrene is preferably in the range of 20 to 50 wt%.

In the case of a multi-component system such as the resin composition of the present invention, it is preferable that the polymers to be blended have similar viscosity balance and skeleton, and the polypropylene resin as the skeleton of the resin C is the same as the resin A. Having a skeleton is preferable for reasons such as suitability for high speed lamination.

The viscosity relationship between resin A and resin B is as follows.
Shear rate 10 1 to 10 2 (1
/ Sec), the magnitude relationship of the melt viscosity of the long chain branched polypropylene resin (resin A) and the polystyrene resin (resin B) has a relationship of η (resin A) ≤ η (resin B). It is preferable to have it. This relationship affects the distribution position of polystyrene in the thickness direction of the long-chain branched polypropylene and the dispersion size of polystyrene when the resin composition is formed into a layer.

The dispersion size and dispersion shape of polystyrene are on the order of μm, and when observed from the sealant thickness direction, the dispersion state of polystyrene shows that MD (machine)
direction, the direction of extrusion) is preferably elliptical to acicular. That is, the size after stretching is preferably 10 to 100 μm. However, even if it is 100 μm or more, there is no problem in physical properties.
Generally, a special alloying technology that disperses the dispersion size to the order of μm or less is required to remove the string of the easy peel sealant and to eliminate fuzz, but the polystyrene dispersion state is in the μm order (10 to 100 μm). In addition, it is possible to efficiently break the base polymer by dispersing it in an elliptical shape (elliptical plate shape from the overall image) and in the thickness direction, and introducing a special alloying technology. Even if it does not exist, it is possible to add a stringing improvement effect. Regarding the dispersed form, the stretching in the MD direction is affected by the processing speed as well, so that it tends to be dispersed in an elliptical shape at a low speed, and into a needle shape at a high speed. I do not receive it.

As for the distribution of polystyrene in the thickness direction of the sealant layer, it is preferable that the polystyrene is uniformly distributed in the entire sealant layer. However, the distribution of the polystyrene dispersed in the polypropylene resin in the thickness direction varies depending on the melt viscosity ratio and the method for forming the sealant film (single layer extrusion or coextrusion) as described above. In particular, when a sealant film is formed by coextrusion, whether polystyrene is distributed near the coextrusion interface or near the sealant layer surface layer is determined depending on the magnitude relationship of the melt viscosity. This content means that the polystyrene phase is locally separated, and as a result, even if the polystyrene content is the same, the apparent polystyrene content changes due to the change in the processing speed (shear rate), which results in peeling. Affect strength. Further, this content may cause a problem of fuzzing after peeling. In this sense, it is possible to eliminate the local separation of the polystyrene phase in the sense of providing stable peel strength or eliminating fluff at any processing speed (shear speed). As a method like this,
Controlling the thickness of the sealant layer is mentioned, and preferably 1 to 30 μm, more preferably 5 to 20 μm.

When forming the above-mentioned resin composition into a film, the film-forming method is not particularly limited, and various known methods such as extrusion lamination molding, inflation molding and sheet molding are used. It is possible to In addition, in these film formation, it is possible to form a film in the form of a multilayer film by using a method such as coextrusion.

With respect to film formation, it is preferable to apply embossing or the like to the inner surface of the sealant, because the effect of further improving the stringing is obtained. As for the method, in the case of extrusion lamination, embossing can be performed in-line during film formation by embossing the cooling roll. Further, in the case of film formation by inflation, after forming a laminate described below, embossing may be performed as a post-process.

As an index of the easy peeling property, when the sealants are sealed face-to-face or when the polypropylene resin and the laminate are sealed, peeling of the seal portion is performed by cohesive failure of the sealant layer, and the peeling occurs. The strength is preferably in the range of 5 to 20 N / 15 mm. The laminate controlled in this way can also be used as a lid material having an easy peel property for a polypropylene resin container or a composite container made of paper and a polypropylene resin, and a soft packaging material having an easy peel property. Can also be used.

Examples of the laminated body using the resin composition of the present invention are as follows. (1) Thermoplastic resin layer / resin composition layer (2) Thermoplastic resin layer / barrier layer / thermoplastic resin layer / resin composition layer (3) Paper layer / thermoplastic resin layer / resin composition layer This is an example, and the configuration (1) is a type in which the resin composition layer of the present invention is laminated on a base film such as a polyester film or a polyamide film by a known laminating method such as extrusion lamination or dry lamination. This structure is the simplest structure, if necessary, various film layers may be interposed,
It is possible to form a multilayer structure by laminating the resin composition layer as a coextrusion film.

The structure (2) is an example of a structure in which a barrier film such as an ethylene-vinyl alcohol copolymer, an aluminum foil, an aluminum vapor deposition film or an inorganic compound vapor deposition film is interposed, and is the same as the example of (1). Other various layers may be interposed.

The configuration of (3) is an example in which it is combined with paper, and the type of paper is not particularly limited. Also in this configuration, various film layers and barrier layers may be interposed similarly to (1) and (2).

Further, in order to impart a design property, it is possible to perform various kinds of printing by a known method, and the type of ink and the printing method are not limited.

[0042]

EXAMPLES Examples of the present invention will be shown below, but the invention is not limited thereto. Further, in carrying out the following examples, the following resins were used. [Material] Long chain branched polypropylene resin (LCB-PP) LCB-PP-1: Long chain branched homo-polypropylene resin (MI = 30) LCB-PP-2: Long chain branched block-polypropylene resin (MI = 16) -Polystyrene (PS) PS-1: Polystyrene (MI = 2.1 general-purpose type) PS-2: Polystyrene (MI = 10 general-purpose type) -Graft polymer (PP-g-PS) G-1: Pendant Polystyrene graft (LCB-
Graft with a polystyrene content of 30 wt% using PP-1 G-2: Pendant polystyrene graft (LCB-)
Graft with polystyrene content of 50 wt% using PP-2)

[Evaluation of Physical Properties of Material] The magnitude relationship of melt viscosity was measured by a capillograph. Measurement condition is temperature 2
Shear rate 10 1 to 10 2 (1
/ Sec) range (barrel diameter 9.55 mm, capillary length 10 mm, capillary diameter 1 mm). As a result, the relationship between the melt viscosity of the long-chain branched polypropylene resin and polystyrene is the melting of the long-chain branched polypropylene resin. The viscosity was smaller than the melt viscosity of polystyrene and had the above-mentioned relationship.

[Preparation of Laminated Body] FIG. 1 is a schematic view showing the laminated body of the present embodiment in cross section. Biaxially stretched polyester film (25μ
An unstretched polypropylene film (20 μm) was laminated on m) by the dry lamination method. Using the laminate of the polyester base material layer 1 and the cast polypropylene resin layer 2 as a base material, a resin composition having the constitution of the following examples was laminated by an extrusion laminating method. that time,
In the extrusion, a long-chain branched polypropylene resin, which is the base of the resin composition, was used as the coextrusion supporting layer 3. The thickness of the coextrusion supporting layer 3 and the sealant layer 4 is 20 μm and 15 μm, respectively. The processing conditions at that time are: a coextrusion laminator (feed block type) at a processing temperature of 290 ° C.
Processing speed 80 m / min. Is. In addition, the inner surface of the seal was embossed by previously embossing the cooling roll.

[Evaluation Method-1] The above laminate of the present invention,
Overlay adherends and heat sealer 160-200
Sealing was carried out at a temperature of 0.3 MPa, a pressure of 0.3 MPa, and a sealing time of 1 second.
The peeling evaluation sample was peeled at a peeling speed of 300 mm / mi.
n. The peel strength and the peel appearance were evaluated by T-type peeling.

[Evaluation Method-2] The laminate described above was evaluated using a tray made of polypropylene resin. Water was selected as the content, and it was sealed when it was full. After that, 95 ° C.-30 min. By performing the boil treatment and the retort treatment at 130 ° C., it was confirmed that the seal strength was decreased before and after each treatment.

[Evaluation method-3] A composite paper container (tray shape) in which the above-mentioned laminate is made of paper and polypropylene resin.
By sealing with, the step filling property was evaluated. Regarding the step filling, a small amount of colored terpine oil was dropped into the tray, and after sealing, terpine oil was poured into the step portion, and the leak condition was confirmed.

[Evaluation Method-4] Platinum vapor deposition was applied to the peeled surface of the peeled sample obtained in Evaluation Method-1, and the dispersed state of polystyrene was confirmed by a scanning electron microscope. As a result, the polystyrene resin was dispersed like needles in the MD direction on the order of several tens of μm.

<Example 1> LCB-PP-1, PS-
The above evaluations were carried out with the compounding ratio of 1 and G-1 being 65/35/15.

<Example 2> LCB-PP-1, PS-
The said evaluation was performed by setting the compounding ratio of 2 and G-1 to 70/30/10.

<Example 3> LCB-PP-2, PS-
The above evaluations were carried out with the compounding ratio of 1 and G-2 being 80/20/5.

<Example 4> LCB-PP-2, PS-
The above evaluations were carried out with the compounding ratio of 1 and G-2 being 65/35/15.

<Example 5> LCB-PP-2, PS-
The said evaluation was performed by setting the compounding ratio of 2 and G-2 to 75/25/5.

<Example 6> LCB-PP-2, PS-
The said evaluation was performed by setting the compounding ratio of G-2 and G-2 to 70/30/10.

<Comparative Example 1> LCB-PP-1, PS-1
Was evaluated with the compounding ratio of 65/35.

<Comparative Example 2> LCB-PP-2, PS-2
Was evaluated at the compounding ratio of 75/25.

[0057]

[Table 1]

As a result, in the examples of the present invention, the peel strength is stable irrespective of the sealing temperature, and it is possible to impart heat resistance without lowering the peel strength even after the boil or retort treatment. . It was also confirmed that the addition of the graft polymer is effective for controlling the strength of the blend interface between the polypropylene resin and the polystyrene resin, and as a result, the fluffing and the peeling appearance are improved.

[0059]

As can be seen from the above results, the resin composition and laminate of the present invention are based on a polypropylene resin which has been difficult to process in the past. By using it, not only the stability of the peel strength but also the heat resistance can be imparted without significantly lowering the peel strength after the boil / retort treatment. Furthermore, by adding the graft polymer, appearance defects such as fluffing and stringing after opening are not caused. Furthermore, by using a polypropylene resin having a relatively high MI as a base, it is possible to impart adhesion even to a stepped portion such as a composite paper tray. As described above, the laminate of the present invention can be used as a lid material or a flexible packaging material for various general-purpose containers in the sense of content protection and a barrier-free viewpoint that has been attracting attention in recent years. Furthermore, it can be deployed in containers that require boiling or retort.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of a laminate according to an example of the present invention.

[Explanation of symbols]

1 ... Polyester substrate layer 2 ··· Cast polypropylene resin layer 3 ... Coextrusion support layer 4 ... Resin composition layer (sealant layer)

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Claims (7)

[Claims]
1. A long chain branched polypropylene homopolymer or a long chain branched polypropylene block polymer (resin A) 50 to 9 having a melt index of ASTM D1280 of 0.1 to 50 g / 10 min.
1 to 50w of polystyrene (resin B) for 9wt%
In a resin composition in which 0.01 to 20 parts by weight of a graft polymer (resin C) obtained by grafting a polystyrene resin on a polypropylene resin is mixed with 100 parts by weight of the above resin A + resin B, the grafting of A resin composition, wherein the structure of the polymer (resin C) exhibits the following features. (1) The weight ratio of polypropylene to polystyrene in Resin C is 50 to 99 wt% of polypropylene and 1 to 50 wt% of polystyrene. (2) The resin C has a structure in which a polypropylene group is grafted in a branched or pendant form in the polypropylene main chain by utilizing a reactive group introduced at the polystyrene end or in the polystyrene main chain. (3) The basic skeleton of the polypropylene resin forming the resin C is the resin A.
2. A shear rate of 10 at a temperature of 260 to 300 ° C.
The magnitude relationship between the melt viscosity η (resin A) of the resin A and the melt viscosity η (resin B) of the resin B in the range of 1 to 10 2 (1 / sec) is such that η (resin A) ≦ η (resin B) The resin composition according to claim 1, having a relationship.
3. The resin composition according to claim 1 or 2,
A laminate having a sealant layer in a thickness range of 1 to 30 μm.
4. The dispersion size of the polystyrene resin (resin B) dispersed in the long-chain branched polypropylene resin (resin A), which is the base resin of the sealant layer, is on the order of μm and observed from the sealant thickness direction. The laminated body according to claim 3, wherein the dispersed state of the polystyrene is an elliptic to acicular state stretched in the MD direction.
5. When the sealants are sealed side by side, or when the polypropylene resin and the laminate are sealed, peeling of the seal portion is performed by cohesive failure of the sealant layer, and the peel strength is 5 to 20 N /. The layered product according to claim 3 or 4, wherein the layered product has a thickness of 15 mm.
6. The laminated body is used as a lid material having an easy peeling property for a polypropylene resin container or a composite container made of paper and polypropylene resin. The laminate described.
7. The laminate according to claim 3, wherein the laminate is used as a soft packaging material having an easy peel property.
JP2001296697A 2001-09-27 2001-09-27 Resin composition and laminate Pending JP2003105143A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006264334A (en) * 2005-03-22 2006-10-05 Curwood Inc Packing laminate, and article manufactured from it

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006264334A (en) * 2005-03-22 2006-10-05 Curwood Inc Packing laminate, and article manufactured from it

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