JP3655090B2 - Bag with synthetic resin chuck - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bag body with a synthetic resin chuck having a chuck having a reopening / closing function at an opening.
[0002]
[Prior art]
In general, a bag body portion and a chuck portion are formed separately, and then both are integrated to obtain a synthetic resin-made zippered bag. By doing so, it is possible to increase the productivity and to obtain a synthetic resin-made zipper-attached bag body that has preferable aptitude as a bag body part and preferable aptitude as a chuck part.
[0003]
[Problems to be solved by the invention]
For integrating both the bag body portion and the chuck portion which are separately molded and provided, the high-frequency weld method and the heat seal method are representative. The high-frequency weld method is superior in preventing heat deterioration and sealing unevenness on the bag surface and improving workability, but there is a problem that it cannot be applied to olefin-based resins with poor polarity. .
[0004]
For example, there is a method of copolymerizing a comonomer containing a polar group, but there is a problem that the application of the comonomer causes a decrease in rigidity. Decrease in rigidity of the chuck part, which is fatal in discussing the biting strength of the chuck part. Although there is a conventional example in which application of the high-frequency weld method has been examined, it has not yet provided a satisfactory chuck. is the current situation.
[0005]
The object of the present invention is to extend the application of the high-frequency weld method to olefin-based resins for separately integrating the bag body and the chuck, and in addition to the preferable suitability as the bag body, sufficient strength and preferable as a chuck It is to provide a bag body with a synthetic resin zipper that has suitability.
[0006]
[Means for Solving the Problems]
The structure of the present invention for achieving the above object is a bag with a chuck comprising a bag main body part and a chuck part as claimed in claim 1 , wherein the bag main body part has an ethylene unit of 60 to 95% by weight. Comprising a copolymer of ethylene and an unsaturated ester having 40 to 5% by weight of a saturated ester unit, and the chuck part is (A) a copolymer of ethylene and an unsaturated ester, or a copolymer of ethylene and an unsaturated carboxylic acid 60 to 95% by weight of the ethylene component in the coalescence and (B) unmodified polyethylene or polyethylene modified with unsaturated carboxylic acid or derivative thereof or a mixture of both, (A) ethylene and unsaturated ester in the chuck part Or an unsaturated ester or unsaturated carboxylic acid component of a copolymer of ethylene and an unsaturated carboxylic acid, and (C) a polyamide component, And it is characterized in that a mixture of the 5 wt% (A) ~ (C) .
[0007]
As described in claim 2, in the above structure, the bending elastic modulus of the resin composition of the chuck portion is 1,000 to 3,000 kg / cm 2.
[0008]
As described in claim 3, in the above structure, (B) unmodified polyethylene, unsaturated carboxylic acid or polyethylene modified by a derivative thereof, or a mixture of both in the chuck portion has a flexural modulus of 1,000 to 3; , 1,000 kg / cm 2 of polyethylene.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. As is well known, a bag body with a synthetic resin chuck has a chuck portion in which a re-openable / closable chuck is bonded and integrated with an opening portion of a bag main body portion. Regarding the integration of the chuck portion and the bag main body portion, either the upper or lower or upper and lower sides of the chuck portion and the bag main body portion are bonded and integrated by a high-frequency weld method.
[0010]
The bag body is made of a copolymer of ethylene and an unsaturated ester. Specifically, the unsaturated ester of this copolymer is preferably methyl acrylate, methyl methacrylate, or vinyl acetate. And ethyl acrylate, butyl acrylate, propyl acrylate, ethyl methacrylate, butyl methacrylate, vinyl propionate, vinyl butyrate and the like. Moreover, you may mix and use these.
[0011]
When the copolymer of ethylene and unsaturated ester is in the range of 60 to 95% by weight of ethylene units and 40 to 5% by weight of unsaturated ester units, the flexibility required as a bag is obtained, Further, the high frequency weld method can be applied. However, if the amount of unsaturated ester increases, there is a problem that the slider is easily worn when the slider is used to open and close the chuck. Conversely, if the amount of unsaturated ester is small, it is necessary to increase the temperature condition. Since problems such as the inability to use equipment appear, it is preferable to set the ethylene unit in the range of 70 to 85% by weight and the unsaturated ester unit in the range of 30 to 15% by weight.
[0012]
The chuck part was modified with (A) a copolymer of ethylene and an unsaturated ester, or a copolymer of ethylene and an unsaturated carboxylic acid, (B) unmodified polyethylene or an unsaturated carboxylic acid or a derivative thereof. It consists of polyethylene or a mixture of both, and a mixture of (C) polyamide (A) to (C).
[0013]
The amount of each component (A), (B), and (C) in the chuck portion is 10 to 94% by weight for component (A), 3 to 70% by weight for component (B), and 3 to 30% for component (C). However, it is necessary to further set conditions in order to make it possible to apply a high-frequency weld method and to have a bending elastic modulus necessary for a chuck.
[0014]
That is, (A) the ethylene component in the copolymer of ethylene and unsaturated ester, or the copolymer of ethylene and unsaturated carboxylic acid, and (B) unmodified polyethylene or unsaturated carboxylic acid or its 60 to 95% by weight of polyethylene modified by a derivative or a mixture of both, (A) copolymer of ethylene and unsaturated ester, or copolymer of ethylene and unsaturated carboxylic acid in the chuck part By setting the saturated ester or unsaturated carboxylic acid component and the (C) polyamide component to be in the range of 40 to 5% by weight, the high frequency weld method can be applied, and the former is 70 to 85% by weight. %, The latter is more preferably set in the range of 30 to 15% by weight.
[0015]
Next, in order to have the suitability as a chuck, further condition setting is required. That is, the occlusal strength required for the chuck of the bag with the chuck varies depending on the weight of the contents and the like, but generally 1.8 to 2.7 kg / 15 mm is desired.
[0016]
When the flexural modulus is 1,000 kg / cm 2 or less, this bite strength cannot be obtained unless the chuck is made large. On the other hand, when the flexural modulus is 3,000 kg / cm 2 or greater, the bite strength is surely increased, but flexibility is increased. It becomes poor and is not preferable. Therefore, it is desirable that the flexural modulus be set within the range of 1,000 kg / cm2 to 3,000 kg / cm2.
[0017]
In order to secure a range of bending elastic modulus 1,000 kg / cm2 to 3,000 kg / cm2 necessary for the chuck, which is applicable to the high frequency weld method, B) It is desirable that the unmodified polyethylene, the polyethylene modified with an unsaturated carboxylic acid or a derivative thereof, or a mixture of both be a polyethylene having a flexural modulus of 1,000 kg / cm2 to 3,000 kg / cm2. However, it is not limited to this.
[0018]
By making (B) unmodified polyethylene of the chuck part or polyethylene modified with an unsaturated carboxylic acid or derivative thereof or a mixture of both into a polyethylene having a flexural modulus of 1,000 kg / cm2 to 3,000 kg / cm2, Regardless of the mixing ratio of the chuck part (B), (A) a copolymer of ethylene and unsaturated ester or a copolymer of ethylene and unsaturated carboxylic acid in the chuck part and (C) of the chuck part By examining the blending ratio of the polyamide, the high-frequency weld method can be applied, and the bending elastic modulus necessary for the chuck can be ensured.
[0019]
Specifically, an ethylene / methyl methacrylate copolymer is applied to (A) of the chuck portion, and nylon-6 is applied to (C) of the chuck portion, and an unsaturated ester (methyl methacrylate) in the ethylene / methyl methacrylate copolymer is applied. When the acrylate) content is 20% by weight, the flexural modulus is 1,000 kg / cm2-3, if the ratio of the component (A) to the component (C) is in the range of 5.7: 1 to 1: 1. When the unsaturated ester (methyl methacrylate) content is 20% by weight or more, the blending ratio of the component (C) is increased, and when it is 20% by weight or less, the blending ratio of the component (C) Is less than necessary.
[0020]
Instead of the copolymer of ethylene and unsaturated ester, a copolymer of ethylene and unsaturated carboxylic acid may be applied. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, sorbic acid, and mesaconic acid.
[0021]
Regarding the polyethylene modified with (B) the unsaturated carboxylic acid or derivative thereof in the chuck portion, the unsaturated carboxylic acid is as described above, and examples of the derivative include acid anhydrides, esters, amides, imides, Metal salts and the like can be raised. Specifically, maleic anhydride, methyl acrylate, methyl methacrylate, maleic acid monoethyl ester, acrylamide and the like can be raised. Of these, modified polyethylene with maleic anhydride is preferred. And then. This modified polyethylene is applied when it is necessary to improve the mixing state with the components (A) and (C) of the chuck portion.
[0022]
In order to modify polyethylene with these unsaturated carboxylic acids or derivatives thereof, the method is not particularly limited, and various known methods can be used. For example, it progresses by adding a radical initiator and heating polyethylene and maleic anhydride in the presence or absence of a solvent. The unit of the unsaturated carboxylic acid or derivative thereof in the modified polyethylene thus obtained is suitably 0.001 to 15% by weight, preferably 0.01 to 10% by weight.
[0023]
The (A) copolymer of ethylene and unsaturated ester or the copolymer of ethylene and unsaturated carboxylic acid in the chuck part has an action of increasing the adhesive strength with the bag body part, (C) Polyamide has the effect of increasing the rigidity of the chuck without deteriorating the high-frequency weldability, but it is particularly effective to use nylon 6, nylon 11, or nylon 12.
[0024]
【The invention's effect】
As described above in detail, according to the bag body with a synthetic resin chuck of the present invention, it is possible to apply the olefin-based resin having a problem in the application of high-frequency weld processing, the surface deterioration of the bag body, It is possible to provide a bag body with a synthetic resin zipper that has a seal body with no seal unevenness and also has a preferable aptitude as a bag body and a preferable aptitude as a chuck section at a relatively low cost. In particular, in the present invention, as described above, the chuck part is (A) an ethylene component in a copolymer of ethylene and an unsaturated ester, or a copolymer of ethylene and an unsaturated carboxylic acid, and (B) unmodified polyethylene. Or 60 to 95% by weight of a polyethylene modified with an unsaturated carboxylic acid or a derivative thereof or a mixture of both, (A) a copolymer of ethylene and an unsaturated ester, or ethylene and an unsaturated carboxylic acid in the chuck part Since the unsaturated ester or unsaturated carboxylic acid component of the copolymer and the (C) polyamide component are composed of a mixture of 40 to 5% by weight of (A) to (C), (C) polyamide The effect of increasing the rigidity of the chuck without reducing the high-frequency weldability due to the components is ensured, and the bending elastic modulus necessary for the chuck is ensured.
[0025]
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[0026]
[Example 1]
Bag body: Copolymer of ethylene and methyl methacrylate
(Ethylene content 80% by weight, MFR3)
Chuck part: (A) Copolymer of ethylene and methyl methacrylate
(Ethylene content 80 wt%, MFR3)-45 wt%
(B) Linear low density polyethylene
(Density 0.930 g / cm3, MFR5) -40 wt%
Linear low density polyethylene modified with maleic anhydride.
(Density 0.92g / cm3, MFR3.5)-5% by weight
(C) Nylon 6
(Specific gravity 1.14, relative viscosity 3.75)-10% by weight
Using the mixture of (A), (B), and (C), a bag with a chuck was manufactured by a high frequency welding method. The high-frequency weldability, the occlusion of the chuck portion, and the wear resistance were evaluated by visual observation and feeling, and the flexural modulus was measured according to JIS K-7106. The results are shown in Table 1.
[0027]
[Example 2]
Bag body: Copolymer of ethylene and methyl methacrylate
(Ethylene content 80% by weight, MFR3)
Chuck part: (A) Copolymer of ethylene and methyl methacrylate
(Ethylene content 75% by weight, MFR7)-60% by weight
(B) Maleic anhydride modified product of linear low density polyethylene
(Maleic anhydride content 0.2% by weight, MFR5)-26% by weight
(C) Nylon 6
(Specific gravity 1.14, relative viscosity 3.75)-14% by weight
A bag with a chuck was manufactured in the same manner as in Example 1 and evaluated. The results are shown in Table 1.
[0028]
[Comparative Example 1]
Bag body part: same as Example 1 Chuck part: (A) same as Example 1 -50% by weight
(B) Same as Example 1 --- 50 wt%
(C) Not applicable A bag with a chuck was produced in the same manner as in Example 1 and evaluated. The results are shown in Table 1.
[0029]
[Comparative Example 2]
Bag body part: same as Example 2 Chuck part: (A) same as Example 2 --70 wt%
(B) Same as Example 2 -30 wt%
(C) Not applicable A bag with a chuck was produced in the same manner as in Example 2 and evaluated. The results are shown in Table 1.
[0030]
[Table 1]
Example 1 Example 2 Comparative Example 1 Comparative Example 2
High frequency weldability Chuck-Chuck ○ ○ × ○
Chuck body ○ ○ ○ ○
Occlusal ○ ○ ○ ×
Abrasion resistance ○ ○ ○ ×
Flexural modulus (kg / cm2) 2,000 1,700 1,400 850
(Note) ○: Good ×: Bad

Claims (3)

It is a bag with a chuck composed of a bag body and a chuck, and the bag body is made of a copolymer of ethylene and an unsaturated ester having an ethylene unit of 60 to 95% by weight and an unsaturated ester unit of 40 to 5% by weight. The chuck part is (A) a copolymer of ethylene and an unsaturated ester, or an ethylene component in a copolymer of ethylene and an unsaturated carboxylic acid, and (B) unmodified polyethylene or unsaturated carboxylic acid or a derivative thereof. 60 to 95% by weight of the polyethylene modified by the above or a mixture of both, (A) Unsaturation of copolymer of ethylene and unsaturated ester or copolymer of ethylene and unsaturated carboxylic acid in chuck part The ester or unsaturated carboxylic acid component and the (C) polyamide component are composed of 40 to 5% by weight of a mixture of (A) to (C). Bag body with a resin-made chuck. The bag body with a synthetic resin chuck according to claim 1, wherein the bending elastic modulus of the resin composition of the chuck portion is 1,000 to 3,000 kg / cm2. The (B) unmodified polyethylene or polyethylene modified with an unsaturated carboxylic acid or a derivative thereof in the chuck portion or a mixture of both is a polyethylene having a flexural modulus of 1,000 to 3,000 kg / cm 2. Item 3. A bag with a synthetic resin chuck according to Item 2.