JPH0551024B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a novel maleic acid-modified linear low-density polyethylene composition having good adhesive properties. [Background of the Invention] Linear low-density polyethylene is a thermoplastic resin with excellent properties such as thermal stability, chemical resistance, and weather resistance, and is widely used as blow molded products, injection molded products, films, and fibers. It is used. However, while linear low-density polyethylene is a highly versatile resin, it has a fundamental problem in that it has extremely poor adhesive properties because it does not have a polar functional group in its molecule. In order to compensate for the above-mentioned drawbacks of linear low-density polyethylene, a method has been used in which linear low-density polyethylene is modified using a polar substance such as maleic anhydride. Linear low-density polyethylene modified with maleic anhydride or the like is basically desired to have good adhesive properties, and it is also desired that there is little variation in adhesive strength due to bonding temperature. That is, when using maleic acid-modified linear low-density polyethylene as an adhesive, the modified product is heated to, for example, about 130 to 220°C to melt it before use. At this time, the adhesive strength changes depending on the heating temperature, and the adhesive strength in the region where the heating temperature is low is generally considerably lower than the adhesive strength in the region where the heating temperature is high. However, if the variation in adhesive strength due to adhesive temperature is large (temperature dependence of adhesive strength), a slight temperature change will have a large effect on adhesive strength. Strict temperature control is required, which complicates the bonding process. Therefore, it is desired that the temperature dependence of the adhesive strength be small in terms of adhesive strength stability and workability. [Known art and problems thereof] Generally, the maleic acid component graft-polymerized to linear low-density polyethylene (in the present invention, the expression "maleic acid component" refers to maleic anhydride and graft-polymerized maleic acid component unless otherwise specified) It is preferable that the amount of (referred to as maleic acid) is large from the viewpoint of adhesion, but as the grafting progresses, the melt index of the modified product decreases and the moldability of the modified product deteriorates. Therefore, considering the advantages and disadvantages of both adhesion and moldability, it is generally said that a modified product in which about 0.1 x 10 ^-4 mol of maleic acid component is graft-polymerized to 1 g of linear low-density polyethylene is preferred. ing. In particular, when manufacturing a laminate using maleic acid-modified linear low-density polyethylene as an adhesive between nylon and polyolefin by extrusion molding, the moldability of maleic acid-modified linear low-density polyethylene is This will have a substantial effect on gender. As a method for producing maleic acid-modified linear low-density polyethylene having the above-mentioned graft amount of the maleic acid component, a method is used in which a predetermined amount of the maleic acid component is simultaneously graft-polymerized onto the linear low-density polyethylene. However, according to studies by the present inventors, the adhesion of maleic acid-modified linear low-density polyethylene modified by the above method is good under so-called static conditions such as when bonding a steel plate and a polyethylene sheet; The so-called dynamic conditions in which polymeric substances such as nylon and polyolefin in a molten state are bonded together by extrusion molding with maleic acid-modified linear low-density polyethylene interposed between the two as an adhesive may not be sufficient. found. On the other hand, a method is also used in which modified linear low-density polyethylene with a high amount of grafting is produced and then diluted with unmodified polyethylene so that the amount of grafting of the maleic acid component becomes a predetermined amount. Maleic acid-modified linear low-density polyethylene prepared by this method often has good adhesion under static conditions because it contains a modified product with a large amount of grafted maleic acid component.
When maleating, the melt index decreases, which may result in poor moldability, and there is also the problem that the gelation rate of the diluted modified linear low-density polyethylene itself increases. The maleic acid-modified linear low-density polyethylene composition obtained using the above two methods is
No particular improvement was observed regarding the temperature dependence of adhesive strength. [Object of the Invention] An object of the present invention is to provide a novel maleic acid-modified linear low-density polyethylene composition. Furthermore, the present invention has a small temperature dependence of adhesive strength, and has excellent adhesion under static conditions.
The object of the present invention is to provide a maleic acid-modified linear low-density polyethylene composition with good moldability and exhibiting good adhesion even under dynamic conditions. [Summary of the Invention] ^The present invention provides 0.15 × 10 ^-4
High maleic acid-modified linear low-density polyethylene in which more than mol of a maleic acid component is graft-polymerized;
Low maleic acid-modified linear low-density polyethylene in which less than 0.1 x 10 ^-4 mol of maleic acid component is graft-polymerized to 1 g of linear low-density polyethylene with a density in the range of 0.915 to 0.930 g/cm ³ by weight. Ratio: 5:
A maleic acid-modified linear low-density polyethylene composition containing maleic acid in a ratio of 100 to 100:100 and having a melt index in a range of 1 to 20 g/10 minutes. [Detailed Description of the Invention] The maleic acid-modified linear low-density polyethylene composition of the present invention comprises high maleic acid-modified linear low-density polyethylene in which a specific amount or more of a maleic acid component is graft-polymerized, and a maleic acid-modified linear low-density polyethylene that is The main feature is that it contains low-maleic acid-modified linear low-density polyethylene in which a maleic acid component is graft-polymerized, and that its melt index is within a range suitable for extrusion molding. High maleic acid modified linear low density polyethylene is
For 1 g of unmodified linear low density polyethylene,
0.15×10 ^-4 mol or more of the maleic acid component is graft-polymerized. The amount of maleic acid component being graft polymerized is 1 g of linear low density polyethylene.
The amount is preferably in the range of 0.15×10 ⁻⁴ to 5×10 ⁻⁴ mol. The melt index of such high maleic acid modified polyethylene is usually in the range of 0.1 to 20 g/10 minutes (preferably 0.1 to 20 g/10 minutes). High maleic acid modified linear low density polyethylene is
It can be manufactured according to conventional methods. For example, it can be produced by melt-kneading commonly used linear low-density polyethylene and maleic anhydride or maleic acid in the presence of a reaction initiator. Examples of linear low density polyethylene used include:
Ethylene and a small amount of α-olefin having 3 to 10 carbon atoms (e.g. 1-butene, 1-pentene, 1-hexene)
A copolymer with a melt index (MI) of 0.5 to 20 g/10 minutes and a density of 0.915.
~0.930 g/cm ³ , a melting point of 115 to 230°C, and a molecular weight distribution (weight average molecular weight/number average molecular weight) of 2 to 10. Usual maleic acid or maleic anhydride can be used as the modifier. The amount of maleic acid or maleic anhydride used is usually 1.1 to 1.5 times the planned amount of grafting, since these modifiers have high reactivity. t, which is commonly used as a reaction initiator
-Use an organic peroxide-based initiator such as butyl-hydroperoxide. In addition to organic peroxides, cumene dimers such as 2,3-dimethyl-2,3-diphenylbutane and derivatives thereof can also be used.
These reaction initiators have a milder reaction initiation mechanism than organic peroxide-based reaction initiators, so they do not cause gelation due to modification and decrease the melt index of linear low density polyethylene modified with high maleic acid. can be reduced. The reaction initiator is used within the usual amount. For example, 2,3-
When di-t-butyl-hydroperoxide or methyl-2,3-diphenylbutane is used, it is used in an amount of 0.1 to 0.01 times the molar ratio of maleic acid or maleic anhydride. Low-maleic acid-modified linear low-density polyethylene is one in which 0.1 to less than ^{10 -4} mol of maleic acid is graft-polymerized to 1 g of unmodified material. especially
Preferably, maleic acid is graft-polymerized in an amount of 0.01×10 ⁻⁴ to 0.09×10 ⁻⁴ mol. Low-maleic acid-modified linear low-density polyethylene can also be produced according to a conventional method similar to the above-mentioned method for producing high-maleic acid-modified linear low-density polyethylene. That is, for the amount of grafting
It can be produced by melt-kneading a mixture consisting of 1.1 to 1.5 times the amount of maleic acid or maleic anhydride and a reaction initiator according to a conventional method. Generally, the melt index of the low maleic acid modified linear low density polyethylene prepared in this manner is usually within the range of 0.5 to 20 g/10 minutes. In addition, when using linear low density polyethylene when preparing low maleic acid modified polyethylene,
It is preferable to use the same linear low density polyethylene as used in preparing the above-mentioned high maleic acid modified linear low density polyethylene. By doing this, the amount of high maleic acid modified linear low density polyethylene used can be reduced,
Decrease in the melt index of the composition can be reduced. High maleic acid modified linear low density polyethylene,
The low maleic acid modified polyethylene is contained in a weight ratio of 5:100 to 100:100.
If the low-maleic acid-modified polyethylene is less than the above range, the amount of high-maleic acid-modified linear low-density polyethylene will inevitably increase, which may lower the melt index of the composition, and if it exceeds the above range, the adhesive properties will decrease. may be low. Maleic acid-modified linear low-density polyethylene compositions containing both in such ranges usually have a maleic acid component in the range of 0.05 to 0.2 x 10 ^-4 mol graft-polymerized to 1 g of the polyethylene component in the composition. It is a composition that has Usually, predetermined amounts of high maleic acid modified linear low density polyethylene and low maleic acid modified linear low density polyethylene are dry blended and then melted and kneaded. The maleic acid-modified linear low-density polyethylene composition of the present invention contains maleic acid-modified products having different amounts of grafting as described above, and has a melt index within the range of 1 to 20 g/10 minutes. The melt index of the composition of the present invention is 1 to 20 g/10
Since the extrusion moldability of the composition is within the range of 200 to 300 min, the extrusion moldability of the composition is good, and the adhesive exhibits good adhesion in a laminate manufactured by extrusion molding using the composition of the present invention as an adhesive. Further, by setting the melt index to the above value or more, a composition with a low gelation rate can be obtained. The melt index of the composition of the present invention is usually adjusted by adjusting the blending amounts of high maleic acid-modified linear low-density polyethylene and low-maleic acid-modified linear low-density polyethylene. The maleic acid-modified linear low-density polyethylene composition of the present invention is usually composed of maleic acid-modified linear low-density polyethylene (high maleic acid-modified linear low-density polyethylene or further low maleic acid-modified linear low-density polyethylene). Contains 20% by weight or more of The maleic acid-modified linear low-density polyethylene composition of the present invention has excellent adhesion, especially under dynamic conditions, and also has good moldability because the melt index is not excessively low. In the maleic acid-modified linear low-density polyethylene composition of the present invention, the high-maleic acid-modified linear low-density polyethylene and the low-maleic acid-modified linear low-density polyethylene act synergistically, resulting in a temperature-dependent adhesive strength. This composition has low adhesive properties and excellent adhesive properties at various bonding temperatures. i.e. 130, which is the normal bonding temperature for maleic acid-modified polyethylene.
Within the temperature range of ~210°C, the difference in adhesive strength with chromate steel plates, for example, is usually 4 kg/cm.
(Instron T-type peeling), and the adhesive strength is also high. The maleic acid-modified linear low-density polyethylene composition of the present invention has good adhesion to polymeric substances such as nylon or polyolefin and metals. Utilizing this property, the maleic acid-modified linear low-density polyethylene composition of the present invention can be used as a heat-fusible adhesive to form a laminate. In particular, a laminate obtained by inflation-molding a polymeric material such as nylon and a polyolefin film using the maleic acid-modified linear low-density polyethylene composition of the present invention as an adhesive has good adhesive properties. are doing. That is, for example, prepare nylon for the outer layer, a maleic acid-modified linear low-density polyethylene composition for the middle layer, and polyolefin such as polyethylene for the inner layer, and use an extrusion molding machine to form the outer layer, middle layer, and inner layer. Manufacturing a laminate in which a polymeric material such as nylon and polyolefin are bonded using a maleic acid-modified linear low-density polyethylene composition as an adhesive by performing inflation molding with the above components. I can do it. The laminate produced in this way is firmly bonded with the maleic acid-modified linear low-density polyethylene composition, and there is little difference in adhesive strength due to differences in molding temperature, so the entire laminate is bonded uniformly. ing. Alternatively, for example, an adhesive sheet (or film) made of a maleic acid-modified linear low-density polyethylene composition formed into a sheet on the surface of a polymeric substance or a metal surface and a polyethylene sheet (or film) are laminated in this order. , 130-210
By heating the adhesive sheet to a softened or molten state at ℃ and pressing it, the maleic acid-modified linear low-density polyethylene composition can be used as an adhesive to attach a polyethylene sheet to the surface of a polymeric substance or a metal surface. Polyolefin sheets (or films) can be adhered. Since such a laminated adhesive has good adhesive properties, the entire bonded laminate does not easily peel off, and is evenly bonded throughout. Next, Examples and Comparative Examples of the present invention will be shown. Example 1 Melt index (MI) 2.0g/10min, density
0.919g/cm ³ , melting point 123℃, molecular weight distribution (Mw/
Mn) 3, linear low density polyethylene (LLDPE) with a butene-1 content of 4% by weight, and 1 g of this LLDPE.
0.1×10 ^-4 mol of maleic anhydride and 0.04
×10 ^-4 mol of t-butyl hydroperoxide was mixed in a Henschel mixer, and the resulting mixture was extruded using a single screw extruder (screw diameter: 50 mm,
L/D=24), heated to 20° C. under a nitrogen atmosphere, and melt-kneaded with a residence time of about 1 minute to produce low maleic acid-modified linear low-density polyethylene A-1. The obtained low-maleic acid-modified linear low-density polyethylene A-1 has 0.07 x 10 ^-4 mol of maleic anhydride graft-polymerized to 1 g of LLDPE.
MI1.5g/10min, density 0.919g/ ^cm3 , and melting point
It was 123℃. Separately, prepare the same linear low density polyethylene (LLDPE) as above, and for 1g of this LLDPE
0.3×10 ^-4 mol of maleic anhydride and 0.096×10 ^-4
High maleic acid-modified linear low-density polyethylene B-1 was produced in the same manner as in A-1 above, except that mol of t-butyl hydroperoxide was used. The obtained high maleic acid-modified linear low-density polyethylene B-1 has 0.23 x 10 ^-4 mol of maleic anhydride graft-polymerized to 1 g of LLDPE.
MI0.7g/10min, density 0.919g/ ^cm3 , and melting point
It was 123℃. After dry-blending 80 parts by weight of the obtained low-maleic acid-modified linear low-density polyethylene A-1 and 20 parts by weight of high-maleic acid-modified linear low-density polyethylene B-1, extrusion used during modification was carried out. A maleic acid-modified linear low-density polyethylene composition was produced by melt-kneading using a machine. The obtained maleic acid-modified linear low density polyethylene composition had an MI of 1.3 g/10 min and a density of 0.919 g/10 min.
cm ³ and the melting point was 123°C. Comparative Example 1 60 parts by weight of LLDPE used in Example 1 and 40 parts by weight of high maleic acid-modified linear low-density polyethylene B-1 were dry blended, and then melt-kneaded using the extruder used for modification. A maleic acid-modified linear low-density polyethylene composition was produced. The obtained maleic acid-modified linear low-density polyethylene composition has 0.092×10 ^-4 mol of maleic anhydride graft-polymerized to 1 g of LLDPE.
MI1.3g/10min, density 0.919g/cm ³ and melting point
It was 123℃. Example 2 In Example 1, low density polyethylene with a melt index (MI) of 2.0 g/10 minutes and a density of 0.922 g/cm ³ was used instead of the low maleic acid modified linear low density polyethylene of A-1. Low maleic acid modified low density polyethylene A- prepared by similar operation
A maleic acid-modified linear low-density polyethylene composition was produced in the same manner except that 60 parts by weight of Maleic acid-modified linear low-density polyethylene B-1 was used. In addition, the maleic acid-modified low-density polyethylene of A-2 is 0.06× per 1 g of low-density polyethylene.
10 ^-4 mol of maleic anhydride had been graft-polymerized, the MI was 1.6 g/10 min, and the density was 0.922 g/cm ³ . The obtained maleic acid-modified linear low density polyethylene composition had an MI of 1.2 g/10 min and a density of 0.920 g/10 min.
cm ³ and the melting point was 108°C. Evaluation of adhesion () Adhesion to chromate-treated steel plate surface A steel plate (SS41 polished steel plate, 6 x 50 x 150 mm) was degreased with trichlorethylene and chromate-treated at 60℃, and a layer of approximately 50 μm thick was applied to the surface of the steel plate. A chromate treatment layer was formed. This steel plate was heated to 140°C, 160°C, 180°C, and 200°C using a heating plate, and the above sheet-shaped body (0.15 x 50 x 150 mm) was laminated on the steel plate and melted for 1 minute. I arrived.
Next, polyethylene sheets (2 x 50 x 150 mm) made of low-density polyethylene with an MI of 0.1 g/10 minutes were laminated, a weight of 5 kg was placed on top of the polyethylene sheets, and the sheets were crimped for 3 minutes, then placed in water. cool,
This was used as a test piece for a peel test. The coating layer of the obtained test piece was 10 mm wide and 150 mm long.
A 90 degree peel test was conducted using an Instron tensile strength tester at a peel rate of 50 mm. The results are shown in Table 1. The adhesive strengths of the maleic acid-modified polyethylene prepared in Examples 1 and 2 at each adhesive temperature are also listed in Table 1.

[Table] As is clear from Table 1, the maleic acid-modified linear low-density polyethylene composition of the present invention has good adhesive properties and has little temperature dependence of adhesive strength. That is, as seen in the modified polyethylenes of low maleic acid-modified linear low-density polyethylene A-1 and high-maleic acid-modified linear low-density polyethylene B-1, and the maleic acid-modified linear low-density polyethylene composition produced in Comparative Example 1. The adhesive strength of normal maleic acid-modified polyethylene tends to decrease to polarity when the bonding temperature is low, whereas the maleic acid-modified linear low-density polyethylene composition of the present invention (produced in Examples 1 and 2) ) has less decrease in adhesive strength due to decrease in adhesive temperature. () Adhesiveness of laminate Inflation molding machine (Die diameter: 100mm,
Lip clearance: 1.25mm)
BUR: 2.0, folding diameter 310 mm, tensile speed 15 m/min, water-cooled inflation conditions, nylon outer layer (manufactured by Ube Industries, Ltd., grade name: 1022FD-1)
30 μm, an adhesive consisting of a modified polyolefin composition produced in the example (or comparative example) in the intermediate layer
20μm, low density polyethylene inner layer (Ube Industries, Ltd.)
A laminate with a three-layer structure of 50 μm was manufactured. The temperature of the extrusion molding machine was set at around 240°C for the outer layer and around 180°C for the middle and inner layers. The obtained laminate was subjected to a T-peel test using an Instron tensile strength tester at a peel speed of 50 mm according to the method specified in JIS-K-6854. Table 2 also shows the adhesive strength of the nylon laminates prepared in Examples 1 and 2, which were molded using polyethylene modified with a maleic acid component as an intermediate layer.

[Table] The laminates using the maleic acid-modified linear low-density polyethylene compositions obtained in Examples 1 and 2 as adhesives had good adhesion between the adhesive layer and nylon and polyethylene. be. On the other hand, for example, the adhesive strength of a laminate produced using the maleic acid-modified linear low-density polyethylene composition obtained in Comparative Example 1 as an adhesive for the laminate shows that the adhesion between the polyethylene and the adhesive layer is good. However, the adhesive has poor adhesion to nylon. An attempt was made to manufacture a laminate using maleic acid-modified linear low-density polyethylene B-1, but since the melt index of this modified polyethylene was low, the resin pressure was 350 kg/cm when extruding with an extruder. ² or more, it was not possible to produce a laminate under the same conditions as the maleic acid-modified polyethylene obtained in Example 1 by motor tripping. [Effects of the Invention] The maleic acid-modified linear low-density polyethylene composition of the present invention combines a modified product with a large amount of grafted maleic acid components and a modified product with a small amount of grafted maleic acid components, so that the effect does not occur when only one is used. In addition to having excellent adhesive properties, the temperature dependence of adhesive strength can be reduced due to the synergistic effect of both.
Therefore, the setting range of the bonding temperature can be widened. Furthermore, the maleic acid-modified linear low-density polyethylene composition of the present invention has good moldability since the melt index is not low.

Claims (1)

[Claims] 1. A high maleic acid modified wire in which 0.15×10 ^-4 mol or more of a maleic acid component is graft-polymerized to 1 g of linear low-density polyethylene with a density in the range of 0.915 to 0.930 g/ ^cm 3 low-density polyethylene, and the density is
The weight ratio of low maleic acid modified linear low density polyethylene in which less than 0.1 x 10 ^-4 mol of maleic acid component is graft polymerized to 1 g of linear low density polyethylene in the range of 0.915 to 0.930 g/cm ³ 5:100~
A maleic acid-modified linear low-density polyethylene composition comprising a maleic acid-modified linear low-density polyethylene composition in a ratio of 100:100 and having a melt index within a range of 1 to 20 g/10 minutes. 2 For 1 g of linear low density polyethylene component in maleic acid modified linear low density polyethylene composition
The maleic acid-modified linear low-density polyethylene composition according to claim 1, wherein a maleic acid component in the range of 0.05 x 10 ^-4 to 0.2 x 10 ^-4 mol is graft-polymerized. 3 High maleic acid-modified linear low-density polyethylene contains 0.15×
The maleic acid-modified linear low-density polyethylene according to claim 1, which is a high maleic acid-modified linear low-density polyethylene in which a maleic acid component in the range of 10 ^-4 to 5 x 10 ^-4 moles is graft-polymerized. Composition. 4 Low maleic acid modified linear low density polyethylene is 0.01x per 1g of linear low density polyethylene.
The maleic acid-modified linear low-density polyethylene according to claim 1, which is a low-maleic acid-modified linear low-density polyethylene in which a maleic acid component in the range of 10 ^-4 to 0.09 x 10 ^-4 moles is graft-polymerized. Polyethylene composition. 5. The maleic acid-modified linear low-density polyethylene composition according to claim 1, wherein at least 20% by weight of the maleic acid-modified linear low-density polyethylene composition is a modified product of the maleic acid component of the linear low-density polyethylene. thing.