JPH0715062B2 - Polyamide film or sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyamide film or sheet. More specifically, the present invention relates to a polyamide film or sheet (hereinafter abbreviated as film) which is excellent in both thermoformability and hot water fusion resistance.

[Prior art]

Thermoforming here means heating the film above the glass transition point (Tg) and then deforming it in various ways.
For example, it refers to vacuum forming using a forming machine such as FC-02F manufactured by Asano Laboratory Co., Ltd.

Thermoforming of polyamide films is only possible at temperatures well above Tg due to the crystallinity of the polyamide. Therefore, for example, in the case of laminating with polyethylene that can be thermoformed at a low temperature, it is necessary to perform thermoforming at a temperature higher than that of a single-layer polyethylene film.

In order to improve this point, for example, nylon 6, which is commonly used, has a low melting point (for example, nylon 6).
6/12, nylon 6/66 copolymerization), there is a method of thermoforming at a lower temperature.

However, polyamides having a low melting point are inferior in hot water fusion resistance to those having a high melting point.

For example, if the outer layer nylon, intermediate layer adhesive resin, and inner layer polyethylene are composed of a three-layer composite film, the film is used to wrap foods, etc. If the fusing property is poor, the nylon on the exterior of the film will fuse and the bag will break when peeled off.

Therefore, the resin for the outer layer of the food packaging film is required to have excellent heat-resistant water fusion resistance.

As an example of improving the thermoformability of the film, for example, JP-A-58-58
There is 124650, but it has not been examined from the viewpoint of hot water fusion.

[Object of the Invention]

As a result of repeated studies by the present inventors to obtain a polyamide film having both excellent thermoformability and heat-resistant water-fusion property,
When a polyamide having a repeating unit represented by the general formula CH _{2 n} CONH- (wherein n represents an integer of 9 to 11) is contained in a polyamide having a low melting point, a polyamide film having excellent properties can be obtained. The present invention has been completed by finding

That is, an object of the present invention is to provide a polyamide film having excellent thermoformability and heat-resistant water-fusing property, which is excellent in processability and has a large commercial value. The gist thereof is (a) general formula CH 1 to 15% by weight of polyamide having a repeating unit represented by _{2 n} CONH- (wherein n represents an integer of 9 to 11), and polyamides 99 to 85 having a melting point of 215 ° C. or less other than (b) and (a)
A polyamide film or sheet for food packaging, which comprises 50% by weight and does not contain a fibrous inorganic filler and has improved resistance to hot water fusion.

[Structure of Invention]

Explaining the present invention in more detail, (a) specifically includes nylon 12, nylon 11, nylon 10 and blends thereof.

The content is 1 to 15% by weight, preferably 5 to 10% by weight
Is. If it is less than 1% by weight, the effect of improving the hot water fusion property is lost, and if it is more than 15% by weight, the gas barrier property is deteriorated and the cost is disadvantageous.

As (b), among the polyamides other than (a), those having a melting point of 215 ° C. or less by the DSC method described later are used. Specific examples of the raw material include lactams such as ε-caprolactam, enantolactam, capryllactam, lauryllactam, α-pyrrolidone and α-piperidone, 6-aminocaproic acid, 7-aminoheptanoic acid and 9-aminononanoic acid. , Ω-amino acids such as 11-aminoundecanoic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid,
Dodecadioic acid, hexadecadioic acid, hexadecenedioic acid, eicosandioic acid, eicosadiendioic acid, diglycolic acid, 2,2,4-trimethyladipic acid,
Dibasic acids such as xylylenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid and isophthalic acid, hexamethylenediamine, tetramethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2, 4 (or 2,4,4)-
Trimethylhexamethylenediamine, bis- (4,4'-
Aminocyclohexyl) methane, diamines such as metaxylylenedeamine, and the like.

Specifically, nylon 6/66, nylon 6 / 6T, nylon 6/6
I, nylon 6/12, etc.

Also included are polyamides such as nylon 6 and nylon 66 having a melting point of 215 ° C. or higher, which are melt-mixed in caprolactam to form polyamides having a melting point of 215 ° C. or lower.

Even if a polyamide having a melting point of 215 ° C. or higher is used as (b),
Although it is possible to improve the hot water fusion resistance by mixing (a), since the thermoformability is deteriorated, (b) has a melting point of 215 ° C or less, preferably 210 ° C to 190 ° C. Is used. Content is 99-85% by weight, preferably 90-
It is 95% by weight.

The polyamide used in (b) is a copolyamide composed of 95 to 25% by weight of a polycapramide component and 5 to 75% by weight of a polyhexamethylene adipamide component (nylon 6/6).
6), Copolyamide (nylon 6 / 6T) consisting of polycapramide component 95-50% by weight and polyhexamethylene terephthalamide component 5-50% by weight, polycapramide component 95-
50 wt% and polyhexamethylene isophthalamide component 5
Copolymerized polyamide (nylon 6 / 6I) consisting of 50% by weight is preferably used.

To mix (a) and (b), any method among ordinary blending methods can be used.

For example, a method of kneading using an extruder, a method of drive blending pellets, and the like.

Further, the film or sheet of the present invention (or the polymer for the raw material of the film or sheet) may optionally contain additives such as a colorant, a nucleating agent, an antioxidant, a lubricant, a heat resistance stabilizer and a weather resistance stabilizer. You can However, in the present invention, the inorganic fibrous filler is not included.

The type of the film or sheet may be either unstretched or stretched, and the polyamide film or sheet may be used in a laminate with another resin film or sheet by a known method such as coextrusion or dry lamination.
However, when the film or sheet is side-witched to another resin film or sheet, the advantage of improving the heat-resistant water-fusion property is not utilized.

As a film forming method, any known method such as a tumbler method or a T-die method can be used.

〔Example〕

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

In addition, the measuring method of the physical property in an Example is as follows.

(1) Surface temperature during thermoforming The film was vacuum formed by the drape forming method using a FC-02F type vacuum forming machine manufactured by Asano Laboratory Co., Ltd. At that time, the film is preheated with a heater before molding, but the surface temperature of the film when the film can be vacuum-formed cleanly (molded according to the mold) was measured with a thermo label manufactured by NOF Giken Kogyo. It can be said that the lower the surface temperature, the better the thermoformability.

(2) Heat-resistant water fusion resistance Water is put into a film formed into a tube and heat-sealed on both sides.

Put 5 of these tubes on top of each other and put them in a water tank.
Heat for 0 seconds. After that, when the outer layers of the tube were peeled off by hand, the fusion property was observed.

(3) Relative viscosity of polyamide resin It was measured according to JIS K 6810 using 98% sulfuric acid.

(4) Melting point It was measured by a DSC (differential scanning calorimeter) method. Specifically, using Perkin Elmer DSCII type, the temperature of the endothermic peak when the temperature was raised at 10 ° C./mm was taken as the melting point.

(5) Oxygen permeability According to ASTM D-1434, the test was performed at 23 ° C.

Example 1 Nylon 6/66 = 85/15 Copolyamide (ηrel 4.5)
(Ε-caprolactam 85% by weight, hexamethy adipate
Polymerized with 15% by weight of diammonium salt)
Amount%, Nylon 12 (MIL's GRILAMID L20) 5 weight
% And ethylene bis-stearamide 0.2% by weight
As an outer blended nylon layer, melt-in the middle layer
Dex (MI) 1.5 adhesive polyolefin resin (Mitsui
Petrochemical Industry Co., Ltd. Admer NF300), MI 0.8 on the inner layer
Polyethylene (NOVATEC-L manufactured by Mitsubishi Kasei Co., Ltd.) F
121), the outer layer 30μ, the middle layer 10μ and the inner layer 40μ
The output film was formed into a film by a water-cooled tuber method.

With respect to this film, the surface temperature of the nylon layer during thermoforming, hot water fusion resistance and oxygen permeability were measured.

Examples 2 and 3 Comparative Example 1 The ratio of nylon 6/66 and nylon 12 used in Example 1 was 6 /.
66: 12 = 90: 10 (Example 2) 6/66: 12 = 97: 3 (Example 3) 6
The same operation as in Example 1 was performed except that / 66: 12 = 70: 30 (Comparative Example 1). The results are shown in Table 1.

Examples 4, 5 Nylon 6 / 6T = 90/10 instead of nylon 6/66 = 85/15
(Ηrel 4.5) (polymerized with 90% by weight of ε-caprolactam and 10% by weight of hexamethylene diammonium terephthalate) (Example 4) Nylon 6 / 6I = 90/10 (ηrel
The same operation as in Example 1 was performed except that 4.5) (a polymer obtained by polymerizing 90% by weight of ε-caprolactam and 10% by weight of hexamethylene diammonium diisophthalate salt) (Example 5) was used. The results are shown in Table 1.

Example 6 Nylon 11 (Rilsan manufactured by Organico) was used instead of Nylon 12.
The same operation as in Example 1 is performed except that BECN) is used.
It was The results are shown in Table 1.

Comparative Examples 2, 3, 4, 5 Nylon 6 (ηrel 4.5) (Comparative Example 2), Nylon 6/66
= 85/15 (ηrel 4.5) (Comparative Example 3), Nylon 6 / 6T = 90
/ 10 (ηrel 4.5) (Comparative example 4) Nylon 6 / 6I (ηrel 4.
5) (Comparative Example 5) A dry blend of 0.2% by weight of ethylenebisstearoamide was used as the outer layer nylon, and the same operation as in Example 1 was performed. The results are shown in Table 1.

Regarding surface temperature during thermoforming, Examples 1 to 6 and Comparative Examples 1 and 3
Polyamide with a melting point of 200 ° C of ~ 5 has a surface temperature of 140 during thermoforming.
However, the polyamide having a melting point of 225 ° C. and nylon 6 of Comparative Example 2 have a melting point of 190 ° C., and it can be seen that the polyamide having a high melting point has poor thermoformability.

Regarding heat-resistant water fusion resistance, as in Examples 1-3, nylon
If 12 is added, fusion does not occur.

In Examples 2 and 3 and Comparative Examples 1 and 3, the content of nylon 12 was changed. When nylon 12 is 30% as in Comparative Example 1, the oxygen transmission rate is significantly increased.

As in Comparative Examples 3 to 5, if Nylon 12 was not added, the bag was completely melted and broken.

The same applies when nylon 11 is used instead of nylon 12 as in the sixth embodiment.

〔The invention's effect〕

Since the film of the present invention has excellent thermoformability and heat-resistant water-fusing property, it is of great value for food packaging and the like.

Claims (4)

[Claims] (A) 1-15% by weight of a polyamide having a repeating unit represented by the general formula CH _{2 n} CONH- (wherein n represents an integer of 9-11) and (b) other than (a) Polyamide 99 to 85 with a melting point of 215 ° C or less
A polyamide film or sheet for food packaging, which comprises 50% by weight and does not contain a fibrous inorganic filler, and has improved heat-resistant water fusion resistance. 2. The polyamide according to claim 1, wherein the polyamide having a melting point of 215 ° C. or lower is a copolyamide comprising 95 to 25% by weight of a polycapramide component and 5 to 75% by weight of a polyhexamethylene adipamide component. Film or sheet. 3. The polyamide according to claim 1, wherein the polyamide having a melting point of 215 ° C. or lower is a copolyamide composed of 95 to 50% by weight of a polycapramide component and 5 to 50% by weight of a polyhexamethylene terephthalamide component. Film or sheet. 4. The polyamide according to claim 1, wherein the polyamide having a melting point of 215 ° C. or lower is a copolyamide composed of 95 to 50% by weight of a polycapramide component and 5 to 50% by weight of a polyhexamethyleneisophthalamide component. Film or sheet.