JPS5828352A - Transparent shrinkable sheet consisting of single layer or multilayer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to transparent shrinkable sheets consisting of a single layer or multiple layers, in which the layers, or in the case of multiple layers, at least one layer, consist of boriad.

Boria sheets, also known as single-layer sheets or multi-layer sheets, are widely used in the packaging industry, especially in food packaging. The polyamide sheet is particularly good for its high strength and low 11! ! Used based on elementary permeability. In addition to high strength, the polyamide sheet combined with the polyolefin sheet, i.e. as a multilayer sheet, has good heat-sealing properties, which, combined with the high melting point of Boria 2D, results in ease of processing and reliable sealing.

The polyolefin layer is then the inner layer of the packaging, ie opposed by the easy-to-seal layer, while the polyamide layer, as an outer layer with a high melting point, prevents adhesion to the heat-sealing jaws. Moreover, since the polyolefin layer has a significantly lower moisture permeability than the polyamide, the two plastics complement each other advantageously and a multilayer sheet of polyamide F and polyolefin is an almost ideal packaging sheet.

The disadvantages of conventional polyamide sheets as shrinkable sheets (whether as multilayer sheets or as solo sheets) are, on the one hand, poor shrinkage behavior or low extensibility at typical temperatures, and on the other hand, often a lack of transparency. It lies in the lack of.

Various proposals have therefore already been made to use polyamide sheets for shrink wrapping or to adapt them for that purpose. For example, fiy Italian Patent Application Public Safety No. 17
No. 69510 describes a multilayer sheet of boria if and polyethylene produced by coextrusion, the sheet being uniaxially or biaxially stretched. Western Germany Patent Application Publication No. 2352553 has a similar structure,
A six-layer sheet of linear polyamide or copolyamide and polyethylene is used as a sausage casing, the sausage casing being stretched in the machine direction to improve its shrinkability. German Patent No. 2,850,181 proposes for the same purpose a tube sheet consisting of a mixture of an aliphatic, ie linear, polyamide and an ionomeric resin and/or a modified ethylene/vinyl acetate copolymer. Due to the small shrinkage capacity of these sheets, the high cost of stretching, and the lack of transparency, these proposals have not been popularized in the market except for special purposes. .

The shrink sheet described in German Patent No. 1,461,842 consists of a strip consisting of an aromatic polyamide he structural element and a branched aliphatic diamine, namely a partially aromatic polyamide F, which is stretched at a temperature of 150-160°C. Ru. The sheet has good shrinkage behavior, but the stretching temperatures used are very high, in particular the shrinkage temperature used, 170-190°C, is too high for most shrink-wrapped items and It has the disadvantage of being damaged.

Besides shrinkability, the other main requirement for such packaging sheets is good transparency, which must not be brittle.

The packaging sheet should be as transparent as possible and as glossy as possible so that the packaged filling-t can be evaluated as favorably as possible. In this case, however, the packaging sheet must not be brittle, as is the case with the sheet according to DE 14 61 842, so that damage does not occur under the influence of mechanical loads, for example during transport or during the packaging itself.

It has already been proposed to condense various monomers together to form an amorphous structure in order to improve transparency. Patent Application No. 2309420 proposes a composite sheet of polyamide and polyethylene, in which the polyamide base is C-fa-lactam, 6-aminomethyl-! 1.5.
5-) Consisting of a copolymer of trimethylcyclohexylamine and isophthalic acid, the proportion of isophthalic acid being less than 15% by weight*V.

Similarly, German Patent Application No. 2,558,892, which deals with layered sheets consisting of polyethylene and polyamide F, discloses e-caprolactam and polyamide F as polyamides.
- coextrusion with a copolyamyl polyethylene consisting of a salt (one condensate of hexamethylene diamine and adipic acid). Two proposals point to zero improvements in transparency. A multilayer sheet having a polyamide layer 'Jk consisting of a copolymer of the monomer components mentioned above has an insufficient shrinkage capacity YV.

The known technology shows that one or the other property is improved, such as contractility or transparency, respectively. However, none of the known documents describes the production of sea ML's that can be shrunk at temperatures that are not typical of the products vtJi, yet maintain other desirable properties of the material, such as transparency, airtightness, etc. do not suggest that.

It is therefore an object of the present invention to obtain the following property spectrum in a shrinkable sheet based on polyamide: 1. Good shrinkability at relatively low temperatures, 2. Stretchability at relatively low temperatures, 3. Easy use. Stretchability by energy 4, good physical properties of polyamides, such as viscoelasticity or flexibility, hermeticity, vacuum formability 5, good transparency and high surface gloss 6, e.g. multilayer sheets when combined with polyolefins For good weldability, polyolefins are usually combined to form the weld layer with polyamides, which have a softening point high enough to prevent adhesion to the welding tool.

This object is solved by 1 m of transparent shrinkable sheeting consisting of a single layer or of multiple layers, in which the layers, or in the case of multilayers, at least one jfI, consist of polyamide, in which according to the invention the polyamide layer is linear. Polyamide and/or linear copolyamide and/or elastomer component 85
It consists of a mixture of ~10% by weight and a partially aromatic boria and/or a partially aromatic copolyane F from 15 to 90% by weight and is stretched at a temperature below 120<0>C.

Linear polyamides in the sense of the present invention are understood to mean very common polyamides, such as polyamide 6, polyamide Y66, polyamide V6 10% polyamide 11, polyamide 12, etc., i.e. polyamides composed exclusively of aliphatic components. Ru.

The linear copolyamide is, for example, copolyamide/66.6
/12 and copolyamides such as 69.

The linear copolyamide itself can also be made flexible, for example by means of monomers, for example e-caprolactam.

This further improves the flexibility of the sheet and facilitates its ability to stretch. The concept of linear copolyamides includes small amounts, i.e. up to 15 parts by weight, of alicyclic and aromatic compounds, such as isophthalic compounds, as described in the above-mentioned EP 2 509 420 A1. Also included are acid-containing copolyas jtF. The small amounts of cycloaliphatic and aromatic compounds in the copolyamide are merely responsible for the amorphous structure of the boria 2d within a wide temperature range.

This copolyamide with a small proportion of cycloaliphatic and aromatic compounds is defined in more detail below as a linear, i.e. aliphatic and aromatic component present in equimolar proportions by definition. It should not be mixed with partially aromatic polyamide.

Elastomer for elastomer, for example? Liptadiene and mixtures of polyamides and elastomers, e.g. copolymers consisting of polyether and polyamide segments, such as those sold under the name Pebax', and copolymers consisting of linear polyamide segments and elastomer segments. Contains copolymers.

Partially aromatic polyamide P or partially aromatic copolyamide r
includes polyamides in which the diamine component or the dicarboxylic acid component is present as aromatic and, in the copolyamide, in an equimolar proportion, or at least in a predominant proportion, as aromatic. Aliphatic diamines such as hexamethylene diamine and aromatic dicarzanic acid,
For example, polycondensation products consisting of terephthalic acid and % isophthalic acid are suitable.

Partially aromatic polyamides V in the sense of the invention include in particular the following diamines, such as ethylenecyamine, hexamethylenediamine, decamethylenediamine, dodecamethylenecyamine, 2.2.4- and/or
or polycondensates of 2,4,4-trimethylhexamethylenediamine% m-# and/or p-xylylenediamine and dicarboxylic acids such as isophthalic acid and terephthalic acid.

When an aromatic component is present in the diamine component, examples of the carboxylic acid component include aliphatic dicarboxylic acids such as oxalic acid, adipic acid, and sepacic acid.

Fully aromatic boria, -I Pl, such as aluminum P, are unsuitable for use according to the invention.

As mentioned above, in partially aromatic polyamides, part of the molar aromatic moieties in both the acid component and the amine component may be replaced by corresponding non-aromatic moieties. However, in each case the predominant molar portion of the partially aromatic species must be partially aromatic. This means, for example: When using isophthalic acid as the partially aromatic component49
Mortides can be replaced, for example, by aliphatic dicarboxylic acids, such as adipic acid.

Elastomer components which can be used instead of or together with linear polyamides P or copolyamides may also be used in the form of prefinished mixtures of partially aromatic polyamides and elastomers, such as polybutadiene or nitrile rubber. .

with a polyamide layer consisting of a mixture of linear polyamide and/or copolyamide V and/or elastomer component on the one hand and partially aromatic polyamide P and/or partially aromatic copolyamide R on the other hand, stretched at temperatures below 120°C. Furthermore, the sheets according to the invention are already distinguished by excellent shrinkability and high shrinkage forces at relatively low temperatures. It is therefore possible to shrink-wrap the items without damaging the heat-sensitive items, ie at temperatures that do not damage the filling. As a result of the high shrinkage forces, the fillings are optimally rolled up without undesirable wrinkles, even in the case of different dimensions or irregular shapes.

It has the advantage of preventing leakage of meat juices when packaging Ic meat and meat products, and also has the advantage of improving the appearance of the packaging and the shelf life of the filled product. On top of that, the temperature of the line sheet is relatively low W,
It is also possible to draw the sheet with relatively low energy consumption, which has the advantage of energy saving and low heat load on the sheet.

Nevertheless, polyamides and copolyamides are known for their good physical properties, such as viscoelasticity or flexibility, which is of great importance with respect to the strength of the packaging, and hermeticity and general use, which are equally important for food packaging. Vacuum formability with the packaging equipment is maintained satisfactorily. In addition, the sheets exhibit improved transparency and high surface gloss, which also significantly enhances the overall optical impression of the equipment constructed from them.

The good shrinkability and high shrinkage forces achieved with the sheets according to the invention are all the more surprising since sheets consisting of the mixture components alone exhibit distinctly poorer stretching and shrinking behavior at the desired stretching and shrinking temperatures. It is. For example, in FIG. 4, curves J and K show the degree of stretching and the shrinkage behavior during uniaxial stretching and shrinkage tests of two types of &IJ sheets made of partially aromatic polyamide, the sheets already having a degree of stretching of 2. It reaches its stretch limit at .3 to 2.7 and then shows tearing. Similarly, the shrinkage is extremely low.

Curve B in FIGS. 1 and 4 shows the stretching and shrinkage behavior of pure polyamide V6 and curve 0 of FIG. 1 of pure copolyamide F69. These curves show that although polyamide Y or copolyamide R has a slightly better shrinkage behavior than partially aromatic polyamide P, the shrinkage behavior does not meet the requirements of the packaging industry.

Unlike that, curve G60? and Muro 0 is linear polyamide 6 and various high proportion partially aromatic polyamides,
Thus, significantly better shrinkage values are obtained with sheets consisting of a mixture of equimolar amounts of hexamethylene diamine and a polycondensate of isophthalic acid, with the higher the proportion of partially aromatic polyamide, the higher the shrinkage values. It shows that it will get better. In other words, the proportion of partially aromatic boriad is 75
Unfortunately, the curve 0 in FIG. 4 shows the best shrinkage behavior.

Preference is given to sheets consisting of a mixture of linear polyamides and/or linear copolyamides and/or elastomer components of 80 to 40 mm and partially aromatic polyamides and/or partially aromatic copolyamides of 20 to 60% by weight. Despite the maximum shrinkage ability when the proportion of partially aromatic polyamide is high, partially aromatic boria tlj2
The reason for taking 0 to 601t is that when the proportion of partially aromatic polyamide P is extremely high, the sheet becomes stiff and brittle.

The maximum shrinkage when the proportion of partially aromatic polyamide is 75% by weight is the same as that of partially aromatic polyamide of one composition of comb, namely hexamethylene iso7 talat F and polyamide v6.
This is also clear from FIG. 2, which shows the increasing degree of stretching during uniaxial stretching of a sheet Y consisting of a mixture of. In contrast, the stretching force shown in the third case of the same sheet used in this uniaxial stretching shows the maximum in an excellent range, i.e., for this sheet at a lower stretching temperature with a relatively low energy usage. Good shrinkage can be obtained. FIG. 5 shows, in accordance with FIG. 6, that for pure partially aromatic lyryamides at a drawing temperature W of 60° C., very high drawing forces have to be used, whereas for the mixtures according to the invention the drawing forces are significantly lower. show.

In contrast, the curve H in Figure 4 shows partially aromatic polyamide V.
It has been shown that a mere 10% by weight does not have a significant effect on the shrinkage behavior.

Hexamethylene isophthalamide and polytrimethylhexamethylene terephthalamide have proven particularly advantageous as partially aromatic polyamides F. These two polyamides already have a proportion of -15i1, preferably 20
Due to its weight, a glass-transparent sheet is obtained, on which the blocking properties, ie mutual adhesion during winding, are reduced, especially when the other mixture component is a linear copolyamide P.

Among the linear & IJ aluminum eOs, polyamide 66 is particularly suitable for the sheet according to the invention. This is because the added and mixed polyamide significantly lowers the softness range V, and as a result, the sheet has a tendency to adhere to the sealing jaws during sealing, thus interfering with the packaging process. This is because polyamide 66, due to its high melting point, prevents a significant decrease in the softening point of the mixture according to the invention.

The sheet containing polyamide 66 and partially aromatic polyamide in the polyamide mixture also contains an amorphous linear copolyamide P, preferably copolyamide 6/661, which has particularly good properties, since partially aromatic This is because the brittleness brought about by the polyamide is offset by this. An excellent composition of the polyamide layer is as follows: Boria is Do 66 40-60 Partially aromatic polyamide by weight 20-60 #Amorphous, linear Coboria is Do 20-50 Partially aromatic polyamide as already mentioned may contain as a further component an elastomer component, in this case also a three-component mixing tube, ie a mixture of partially aromatic polyamide, linear polyamide and elastomer component. In this case, for example, boria (P66) is preferably used to maintain a high softening point, and the elastomer component improves the flexibility of the sheet. As elastomer component linear polyamide segments and elastomers, preferably polyether units, or also Polymers consisting of fine polybutadiene segments have been shown to be advantageous.

The stretching of the sheet, which is a necessary premise for forming shrinkage ability, is 120
Since it is carried out at temperatures below 0.degree. C., the intellectual properties of the sheet are not impaired. Stretching is preferably carried out at 60 DEG to 90 DEG C., with lower stretching temperatures generally being preferred and resulting in higher shrinkage values. Basically, it is low like this, and s′
It is an advantage of the sheet according to the invention that it can be stretched at temperatures as low as 1FO. Although uniaxially oriented also provides a shrinkable sheet, a better overall envelope is created with biaxially oriented sheets in packaging applications.

Stretching is, in uniaxial stretching, the elongation of the sheet strip under the action of tension, and in biaxial stretching, ie stretching in the machine and transverse directions, it is the enlargement of the sheet strip.

The degree of stretching is the ratio of the residual length of the sheet strip after stretching to the IJ length before stretching. Stretching force is the force used for a given degree of stretching.

A particular advantage of the sheet according to the invention is that it can be deep-drawn, i.e. under heating to a defined temperature range and under vacuum or possibly under the action of compressed air, to effect the necessary stretching of the sheet area to be contracted. That's a good enough point. This advantage of the invention is that there is no need to subject the sheet to a separate stretching step, and the power of the deep drawing step is sufficient for the stretching necessary to make the sheet or package well shrinkable.

This eliminates the costly biaxial stretching, and the shrinkage capacity obtained by deep drawing is limited by filling the filler, closing with a cover sheet, welding the edges under package exhaust, and after the sheet is heated. Give the filled product a snug, deflated package.

It is particularly advantageous here that the film according to the invention has an increased shrinkage force compared to the known foam amide film.

The contraction force is a force that can oppose the tension force that acts against the contraction direction during the sheet Y contraction process. High shrinkage forces are important since the gravity of the filling must be overcome when relatively heavy fillings are packaged.

It is of particular importance to combine the two polyamide layers according to the invention with at least one further layer, since this makes it possible in a manner known per se to eliminate the disadvantageous properties of the solo sheet and to add advantageous properties. . Thus, boriacides are generally distinguished by high strength, good deep drawability and a relatively high barrier effect against atmospheric oxygen. Of course high water vapor permeability and disadvantageous melting W7! Behavior is a drawback. This can be compensated in an excellent manner by combining one or more layers of polyolefins, especially polyethylene and its copolymers, deposited on the polyamide V-sheet. Polyolefins have a high water vapor barrier and polyethylene has good weldability. Polyolefin sheets have the disadvantage of too little barrier action against atmospheric oxygen and insufficient strength for many applications. Therefore, the two plastics complement each other advantageously, especially as food packaging sheets.

In an advantageous embodiment of the invention, the sheet according to the invention therefore consists of at least one polyamide layer and at least one polyolefin layer of the composition mentioned above. It is particularly advantageous here that the above-mentioned advantageous properties of the polyamide layer according to the invention remain intact even in combination with polyolefins. 11g Curve V in Figure 11 shows that a layer consisting of a linear coboriaod containing e-caprolactam exceeding 90% by weight (curve D in Figure 1) and a boriamy/polyethylene composite sheet consisting of a low-density homopolyethylene are formed into a linear boria ξF. It is shown that there is typically a decrease in shrinkage capacity at relatively high degrees of stretching. Unlike that, the curve Q%B
and T have good shrinkage values and do not show any tendency for shrinkage to decrease at high degrees of stretching.

The polyamide layer of the sheets of curves S and T is produced from a particularly advantageous six-component combination of r% linear copolyamide and partially aromatic polyamide.

As a polyolefin layer, it already has a high shrinkage force by itself,
Therefore, in combination with the high-shrinkage polyamide layer according to the invention, the entire polyolefin has excellent shrinkage strength, such as is required in deep-drawn packaging, for example.
K is selected.

Polyethylene is particularly suitable as an additional layer to the polyamide layer according to the invention since, along with the other aforementioned good properties of polyethylene, it provides good weldability (depending on the melt index), good shrinkage strength Y4. It is a combination partner. Ethylene copolymers or admixtures thereof are preferably used as the polyolefin layer, especially in order to improve the weldability and not to have any adverse effects on the excellent transparency of the polyamide layer. This also includes in particular ethylene copolymers of the ionomeric resin type, since they have a wide range of variation in their property spectrum. There is a type with a high contraction force, which is selected when a high contraction force is required.
If the filled product cannot withstand high shrinkage force, select one with a small shrinkage force Y.

A polyolefin layer consisting of a polyethylene type, so-called -shaped low-density polyethylene, with a low density, advantageous KO,95511/cgL3 density below and a linear molecular structure is also very suitable, since the composite sheet obtained therefrom has a good Excellent weldability and high mechanical properties! 1iff
This is because it has excellent contractile force.

In order to optimally adapt the composite sheet to the particular application, it is advantageous to produce the polyolefin layer from a mixture of ethylene homopolymers and ethylene copolymers.

The layers are advantageously produced by coextrusion (which may be by blown or flat sheet coextrusion);
and - can be compacted into a composite sheet, which has the advantage of a unique processing step. Flat extrusion methods are particularly advantageous when high transparency is of value.

However, the layers may also be adhered to one another, especially if the nature of the plastic makes coextrusion less suitable, for example. Adhesion preferably includes conventional adhesives consisting of polyurethane adhesives.

In the multilayer sheet according to the invention, the stretching step necessary for shrinkage is preferably carried out by stretching the composite sheet itself. Stretching of the individual layers is also possible, but this involves processing costs and can only be mentioned in individual cases, for example in composite sheets produced by gluing.

Advantageous common stretching is also carried out in particular in the stretching x deep-drawing process, in which case the biaxial stretching carried out in the deep-drawing process in the production of deep-drawn containers is carried out only in the area in which the composite sheet is formed.

The deep-drawn packaging produced in this way from deep-drawn K naturally also requires a cover sheet to close the container airtight from above after filling the filling to be packaged. This cover or closing sheet is generally of a smaller thickness than the lower sheet used for deep drawing using a vacuum Y, since forming under thinning is not carried out.

For this purpose, at least two composite sheets are preferably used, the side facing the vacuum-formed container consisting of a polyolefin, which is in bath contact with the inner layer of the container. The outer layer generally consists of a high-strength sheet, such as a biaxially oriented polyester or polyzolopyrene sheet, a water-containing cellulose sheet or a +V-impermeable and gas-tight sheet, such as an aluminum sheet. The gas permeability of the cover sheet is comparable to the gas permeability of the molded bottom sheet so as to provide the necessary SV protection so that the entire package does not spoil the filler.

A description of each figure follows: Figure 1: Dependence curve of the shrinkage behavior of various FA sheets on the degree of stretching Sheet B Polyamy r6, viscosity 40 Copolyamy r69 D C-caprolactam over 90 weight strength, 3
A copolyamide consisting of -aminomethyl-5,5,5-trimethylcyclohexylamine and isophthalic acid (the two hexamers together are less than 10% by weight) All measurements were carried out at a drawing source f60°C.

Figure 2: Shrinkage due to degree of stretching and mixture formulation. The sheet is a mixture layer consisting of polyamide Amuro and polyhexamethylene inphthalamide of various compositions.

curve Iel Stretching degree 1:1.5 1it 2 1: 2.0 13 1:2.5 14 1:2.75 z5 1:3.0 All measurements were conducted at a stretching temperature of 60°C.

Figure 6: Stretching force depending on the degree of stretching and the mixing recipe.

The composition of the sheet is the same as the sheet in Figure 2.

Curve E6 Stretching degree 1: 1.5 17 //1:2.0 18 #1: 2.5 to 9 1/ 1: 2.75 Ei 10 1/ 1: 3.0 All measurements were conducted at a stretching temperature of 60°C.

Figure 4.2 Dependence of contraction of various P sheets on elongation.

Curve A60 1t? Lihexamethylene inphthalamide 75
Chipolyamide v6, viscosity 4 25 arrogant B Polyamyl r6, viscosity 4 y p muro, viscosity If4 50s polyhexamethylene isophthalamide IIIP 50 steamed G60 P
A6, viscosity [47 layers M polyhexamethylene inophthalide PM 251 11 P unevenness, viscosity! 1.5 90 Polyhexamethylene isophthalamide P Hp i, 10'jJ
Polyhexamethylene InphthalakirK Polytrimethylhexamethylenetere7thalamide All measurements were performed at a stretching source [60°C.

Figure 5: Dependence of the PH receipt stretching force on the degree of stretching.

Curve 1 polyhexamethylene isophthalene door 5 polyamide y6, viscosity 4 25chi B1 po 1J7 (t”6, viscosity [4 yI PA6, viscosity 1j4 50chi/I
J hexamethylene isophthalamin 01 GI P Muro, viscosity 4 75 thimelihexamethylene inophthalamin r 25 HI PA6, viscosity 3.5 90% polyhexamethylene terephthalamin r 10 th Jl polyhexamethylene isophthalamin PK1
Polytrimethylhexamethylene terephthalamide was measured at a stretching temperature of 60°C.

Figure 6: Degree of stretching and yield of shrinkage behavior: a dependence on temperature. The sheet is made of polyhexamethylene iso-7 talamide 75% and P muro, viscosity 4 25%.
Made of a mixture of.

Curve A 60 Stretching at 60° C. Stretching at 9090° C. Stretching at 120 120° C. FIG. 7: Dependence of the stretching force on the degree of stretching and the stretching temperature. The sheet is compatible with the sheet shown in Figure 6.

curve Muro 0-1 Stretched at 60℃ Mu90-1 Stretched at 90℃ A120-1 Stretched at 120℃ Figure 8: Dependence of shrinkage behavior on stretching degree and stretching temperature.

Sheet: polyhexamethylene Mixture of phthalamide and copolyamide Coporia is over 90% by weight C-caprolactam, 6-aminomethane Ther-3,5,5-)limethylcyclo Hexylamine and in7talll1IL.

Curve L60 Stretched at 60° C. L90 Stretched at 90° C. L120 Stretched at 120° C. FIG. 9: Dependence of the stretching force on the degree of stretching and the stretching temperature. The sheet corresponds to the sheet in Figure 8.

Curve L60-1 Stretched r at 60°C, Stretched at 90-190°C L120-1 Stretched at 120°C Figure 10:/Liami V/Ethylene-Vinegar 1!1 Dependence of the shrinkage behavior of the vinyl copolymer sheet on the degree of stretching.

The sheet is made from a polyamide layer made from a mixture of 75% by weight of P Muro and polyhexamethylene isophthalamyl 125% by weight and ethylene and vinyl acetate (31*
Consisting of a polyethylene layer of a copolymer from

FIG. 11 Dependence of the shrinkage behavior of two different Pmu/PI-sheets on the degree of stretching.

The sheet is a PA/PI composite sheet, in which the pm single layer in all sheets consists of homopolyethylene with a density of 0.92297 an3 and a melt index of 0.891/10 min. The lyamide layer had the following composition: Curve cap Milmulo 80% by weight Polyhexamethylene terephthalamyl 20% by weight S P Muro 6 50% by weight Polyhexamethylene isophthalamyl 25% by weight 90i 1 amount. Copolymer of C-caprolactam, 6-aminomethyl-3,5,5-)limethylcyclohexylamine and isophthalic acid 25 wt ST
P Muro 6 50 Coulum - Copolyamyl'6/66 25% by weight Sameethylene isophthalamide 25% by weight V 90% by weight t*v 1-caprolactam, 6-
Copolymer of Aminomethyl-3,5,5-trimethylcyclohexylamine and Isophthalic Acid The invention will now be illustrated in more detail with reference to the Examples.

Example 1 Corresponds to the sheet according to FIGS. 8 and 9.

Copolyamide (melting point 214-21
7°C, rough density L11/α3)5 by D engineering N53479
50% by weight of polyhexamethylene isophthalazade) (melting point: 180"O1 density If 1-19117cm") was mixed into a partially aromatic polyamide produced by diamine and isophthalic acid, and a sheet was prepared. Manufacture.

The two granules were mixed together in a commercially available Taum 1 mixer and processed in an extruder equipped with a slit die, cooling rollers and winder, suitable for processing polyamide F granules commonly used in practice. Thickness i, 060+s+±10
Make it into a flat sheet of es.

The sheet is relatively stiff in bending and has a glass clear appearance and is subsequently stretched.

To measure the extensibility and shrinkability of the sheet, proceed as follows: Sheet pieces were placed in a standard temperature of 25 °C and 50 °C relative humidity to create an equilibrium between the ambient humidity and the humidity of the sheet. Expose and store for 48 hours.

The sheet is then cut in the longitudinal direction, ie, in the extrusion direction, into 15 fin width test strips.

Support length 50.0 with tensile testing machine using D Engineering N51221
Each test case marked with a marking corresponding to m) is fixed in an IJ clamp and heated with a stream of hot air at 60°C, 90°C or 120°C for about 20 seconds. A warm air blower with stepless temperature control was used, and the temperature of each treatment was adjusted by measuring the hot air flow at a distance of 2' Owag from the nozzle opening until the temperature was constant. Tensile test with a tensile tester)
IJ tube'Ik: The same distance was used during heat treatment. After the preheating time, the test piece was held under uniform blowing of hot air (moving up and down against the test piece) while supplying heat from one side to the nest, and on the other hand, the lower clamp of the tensile tester was sent uniformly at 100 IlZ. move it down. Stepwise stretching (ratio of residual final length to initial length between marks) (1 cut each depending on K) The IJ tube is uniaxially stretched to a predetermined stretching section. The maximum stretching force at the end of the stretching process is read by the force measuring device of the tensile tester.

The test strips were kept flat for at least 15 minutes, exposed and stored for elastic elongation.After equilibration, the new distance of the measurement mark was measured at 111! Measure with a scaled ruler and use this as the final length. Then fix one additional 0.2 g weight at each lower end to the IJ tubes to allow sufficient immersion in the liquid bath. each strip t
Heat treat for 5 seconds by rapid immersion in a 95±1° C. water bath. Depending on the degree of elongation, a constant contraction of the length of the strip occurs. New length reduced by shrinkage!
measure. The change in length between the relaxed length and the remaining length after the heat shrinkage process is calculated as the shrinkage percentage.

The results of the shrinkage values at each temperature can be obtained from FIG. 8 and the stretching force values from FIG. 9.

Example 2 Corresponds to the sheet of curve G1 or G60 in Figures 4 and 5.

Relative solution viscosity [4,0, melting temperature 217-221 °C and 1 according to pni 55479 by D Engineering M53724,
Polyamide draw granules 75 having a coarse density of 12 to 1.141/lx<'' were prepared as in Example 1 and made of polyamide 25 of hexamethylene diamine and inphthalic acid, the detailed data of which are given in Example 1. Mix. Mixture 1 Example 1
Process it as shown below. In this example as well, the thickness of the sheet is 0.06 Owax±10q6. The sheet has a high transparency glass transparent appearance. The bending stiffness is slightly higher than the sheet of Example 1.

Further processing is carried out by the processing, stretching and shrinking methods described in Zeaton Example IK. The shrinkage values according to the degree of stretching are shown in Figures 4 and 5.
Picture song Ii! Obtained from 1IG60 or G1.

Example 6 Comparable to the sheets in Figures 6 and 7.

25 weight of polyamide 6 granules as in Example 2 are mixed with 75 weight of polyamide granules of hexamethylene diamine and isophthalic acid as described in Examples 1 and 2 as described above.

From this granule mixture, a sheet having a thickness of 0.060 mm ± 10 inches is produced by adding as described above. The sheet has a highly transparent, glass-transparent appearance and the bending stiffness is higher than the sheets of Examples 1 and 2.

The sheets were measured and evaluated as described above, and the curves according to FIG. 6 were obtained for the shrinkage values, and the associated stretching forces are shown as the curves in FIG. 7.

Example 4 Concerning the production of composite sheets. The sheet is stretched by deep drawing and then the package is made.

Polyurethane adhesive (polyester/polyol 10-hexamethylene diisocyanate) prepared by dissolving Boria [P sheet in ethyl acetate in a conventional sheet laminating device according to Example 1]
After evaporation of the solvent, the dry substance was applied evenly with 1 amount of 2.61 m
"was gotten.

The corona-pretreated surface of the ethylene/vinyl acetate copolymer sheet was pressed onto the adhesive-coated surface with a laminating roller at a rolling temperature of 75° C., facing the adhesive layer, and the sheet was cured at room temperature for 10 days to be laminated. At a peel angle of 180° and a sheet width of 10 mm, a strong bond between the layers was created with a peel strength of 22 Q cN f.

Ethylene/vinyl acetate copolymer sheet is D-Ko N537.
Melt index at 190/2.16 by 35 and 8g
/10 minutes, the average thickness was 0.120 mKH made from granules with a density of 0.928 g and a vinyl acetate content of 5 cm using a commonly used inflation device. After the inflation process, cooling and flattening of the tube, the tube was corona treated. The material is then divided into two single strips in the usual manner and fed to a laminating device for the processing described above.

The above polyamide/ethylene-vinyl acetate copolymer composite sheet was cut into a strip width of 451 tx using a conventional roll cutter, and wound into a 100 meter run sheet roll.

Manufacture of deep-drawn packages: A vacuum deep-drawing machine, usually used for the packaging of foodstuffs, such as sausages, pork, etc., is heated to a heating plate temperature of 90°C.
℃ and molding under vacuum action on the underside of the vacuum mold as a result of the pressure difference with respect to atmospheric pressure. At that time, the polyamide Y side was on the bottom.

The mold was a two-cavity mold with dimensions of 225 m (length parallel to the running direction) x 180 m (width) x 40 m (depth) for each individual mold. The number of cycles was 5 min−1. A meat sausage having an intestine with a length of about 200 toms and a diameter of about 30 tm was used as a filling product. Number: 5 sausages parallel to each other lengthwise.

0-040m thick as a cover sheet? Package made of Liamid 6 sheet and thickness 0.025 wx! A composite sheet consisting of an inner layer of polyethylene specially treated for easy release was used. The cover sheet is placed on the formed and filled lower sheet before the welding station, with the two PE-
The surfaces touched each other. The temperature of the grid-shaped welding tool is 140℃
was pressed onto the sheet, which was supported on a correspondingly shaped corresponding tool. Welding was carried out under simultaneous evacuation inside the package. Behind the welding station, the machine is additionally equipped with a contraction device, which consists of a hollow chamber filled with hot air at a temperature of about 140° C., which rises above the cover sheet towards the id plate. This was done so that it would surround the lower part taken out of the mold according to the cycle of the machine. The sheet wrapped the filling tightly and without wrinkles, and leakage of juice from the filling was prevented by the tight packaging.

The weld line remained wrinkle-free even after the shrinkage process.

EXAMPLE 5 A polyamide sheet according to Example 2 is prepared as in Example 4 and laminated with a sheet made of the same ethylene/vinyl acetate copolymer granules as in Example 4, but with a thickness of 0.060 mm.

Stretching and Shrinkage Behavior of the Resulting Boriamy/Ethylene-Vinyl Acetate Copolymer Composite Sheet 1 Tested in the laboratory under similar conditions as the sheet of Example 1.

The shrinkage value results are obtained from the curves in FIG.

Example 6 Manufacture of co-extruded composite sheets. Polyamide/polyolefin composite sheet manufactured by coextrusion using the t-inflation method.

The coextrusion-inflation device consists of an extruder 1 for the polyamide layer, a single screw extruder with a screw diameter of 60 m, a screw length of 270 mm, and a 3-zone screw with a mixing section in the measuring zone; Extruder 2, screw diameter 30W1Y: high-speed single-screw extruder with heat insulation; extruder 6 for polyolefin layer, screw diameter 60W1, a mating liner with cooling grooves, screw length 270, and a mixing section in the measurement zone. Consisting of a single screw extruder with

For the production of the next sheet, the following is carried out in the three-layer sheet coextruder described above: In extruder 1, linear coboria fy 60 weight parts consisting of 85 weight parts of 8-caprolactam, hexamethylene diamine and 15 weight parts of bolyami F from Adipine. part and melting point 180℃ (
Kofler-method) and density (D-N)
53479) 1.18! Partially aromatic boria (P40 parts by weight of Ml/clIL3) consisting of isophthalic acid and hexamethylene diamine was intensively mixed as granules and treated at a rotation speed of 52 min-1 and a temperature of 240 °C in the screw cylinder and flange, 3 as melt
Layer inflation is applied to the FK supply.

In extruder 2, ionomer resin [DuPont's Sururi y]
(8urlyn) A 1705, zinc as cation] is operated at a rotational speed of 80 min-1 and a cylinder and flange temperature of 210 DEG C.

Extruder 3 has a thickness of 0.9221/cm manufactured by high pressure method.
l- and LD- with melt index 0.81/10 min.
PK (commercially available group: 8tamyxan) 3
72Q
Extrude as inner layer at 0°C.

The 6-layer inflation head Y, which is supplied with 6 types of melt, has an annular slit diameter of 300 sow and slit width of 1.2 mV.
It had a temperature of 260°C.

The total thickness was measured to be 0.160m. Of these, the polyamide layer is 0.055 m long, the adhesion aid layer is 0.015 m long, and the polyethylene layer is 0.090 m long.

Manufactured with an inflation ratio of 1.8:1 (m sea)
It was cut into Y single N material and rolled up.

The sheet had very good transparency.

The IJ tubes stretched as in Example 1 gave the following results in the shrinkage test described in Example 1: Degree of stretching Shrinkage (t4) 2.0 44 2.5 49.5 3.0 54 This sheet is therefore highly suitable for shrink wrapping.

Example 7 Production of another composite sheet by coextrusion and stretching by deep drawing.

1. Via co-extrusion of a three-layer flat sheet as in Example 6. Polyan r with film thickness 65μm, ■, film thickness 15μm
m ionomer resin (as in Example 6) as adhesion aid and ■, film thickness 96 μmO as in Example 6? Manufacture sheets from polyethylene.

Boriaki V layer I is Boriaba doro 650 weight starvation ξ
Dro 766 consists of a mixture of 25 weight bags and 25 weight bags of sameethylene isophthalic acid in polyamide.

These components are intensively mixed before extrusion as granules and the melt is homogenized and extruded into a homogeneous polyamide layer in an extruder with a mixing zone screw.

In the polyamide extruder, increase the cylinder temperature to 280℃,
And the blow molding head temperature is adjusted to 270°C. All other parameters correspond to those listed in Example 6.

The sheets thus produced were cut into single sheets with a Y width of 420 m and processed in a vacuum forming machine according to Example 4 with the same parameters at cycles of 4 and 8 min. The improvement obtained is that even at high welding temperatures and high cycle numbers, no hindrance is observed in the deep drawing process.

The coextruded composite sheet of Example 7 is curve 0 in FIG.
corresponds to Therefore, the +7 tsude drawing shown in the drawing corresponds to the drawing by deep drawing.

[Brief explanation of drawings]

Figure 1 is a diagram showing the dependence of the shrinkage behavior of various PM sheets on the degree of stretching, Figure 2 is a diagram showing the shrinkage depending on the degree of stretching and mixing prescription, and Figure 6 is a diagram showing the degree of stretching and mixing prescription. FIG. 4 is a diagram showing the dependence of shrinkage of Dandan's P sheet on the degree of stretching, and Figure 5 is a diagram showing the stretching force of Dandan's P sheet.
FIG.
FIG. 6 is a diagram showing the dependence of shrinkage behavior on the degree of stretching and shrinkage temperature, FIG. 7 is a diagram showing the dependence of stretching force on the degree of stretching and stretching temperature, and FIG. 8 is a diagram showing the dependence of shrinkage behavior on the degree of stretching and stretching temperature. FIG. 9 is a diagram showing the dependence of the stretching force on the degree of stretching and stretching temperature, and FIG. 10 is a diagram showing the dependence of the stretching force on the degree of stretching and stretching temperature. It is a diagram showing the dependence of shrinkage behavior on the degree of stretching,
FIG. 11 is a diagram showing the dependence of the shrinkage behavior of various Pmu/PI sheets on the degree of stretching. June 27, 1981 Mr. Commissioner of the Japan Patent Office 1. Indication of the case Patent Application No. 80303 of 1988 2. Name of 1 Ming 3. Relationship with the case of the person making the amendment Name of the patent applicant Title: Feldmühle Akchengesellschaft 4. Scope of Claims and Detailed Description of the Invention in Sub-Attorney's Specification, Contents of Amendment (1) The scope of claims shall be amended in a separate document. (2) "Maximum" on page 18, line 5 of the specification is corrected to "minimum". (3) Correct "curve C" on page 47, line 12 to "curve T". 2. Scope of Claims 1. A transparent shrinkable sheet consisting of a single layer or a multilayer, in which the layers, or in the case of multilayers, at least one layer, consists of a polyamide, the polyamide layer being a linear polyamide and/or a linear copolyamide and/or elastomer component 85 Consisting of a single layer or a multilayer, characterized in that it consists of a mixture of ~10% by weight and 15-90% by weight of partially aromatic polyamides and/or partially aromatic copolyamides and has been stretched at temperatures below 120°C Transparent shrinkable sheet. 2. The polyamide layer contains linear polyamide and/or linear copolyamide P and/or polyamide, 80 to 4% by weight of the polyamide component of the lastmer and 20 to 60% by weight of partially aromatic polyamide P and/or partially aromatic copolyamide I. A sheet according to claim 1, comprising a mixture. 3. Claim 1 or 2, wherein the partially aromatic polyamide is polyhexamethylene isophthalamide.
Sheet with section description. 4. The sheet according to claim 1 or 2, wherein the partially aromatic polyamide is polytrimethylhexamethylene terephthalamide. 5. The sheet according to any one of claims 1 to 4, wherein the linear polyamide is polyamide 66. 6. Polyamide layer is polyamide 6640-60% by weight
, a mixture of 20 to 30% by weight of a partially aromatic heptadamide and 120 to 30% by weight of an amorphous linear copolyamide. 7. Any one of claims 1 to 6, wherein the elastomer component is a block copolymer consisting of linear polyamide segments and elastomer segments.
Sheet with section description. 8. The sheet according to any one of claims 1 to 7, wherein the sheet is stretched at a temperature of 60 to 90°C. 9. A sheet according to any one of claims 1 to 8, which is stretched by deep drawing. 10. The sheet according to any one of claims 1 to 10, comprising at least one polyamide layer and at least one polyolefin layer 751. 11. The sheet according to any one of claims 1 to 9, wherein the polyolefin layer is made of a polyolefin having a high shrinkage force. 12. 1'? The lyolefin layer is ethyleneco, t?
12. The sheet according to any one of claims 1 to 11, which comprises an IJ marker). ■4. A sheet according to any one of claims 1 to 13, wherein the polyolefin layer consists of a mixture of different ethylene copolymers. 15. The sheet according to any one of claims 1 to 14, wherein the polyolefin layer has a linear molecular structure and is made of a low-density [(D polyethylene type). 16. The polyolefin layer is an ethylene homopolymer. and an ethylene copolymer. 17. A sheet according to any one of claims 1 to 16, in which the multiple layers are coextruded. 18. The sheet according to any one of claims 1 to 17, wherein the multiple layers are adhered to each other. 19. The sheet according to any one of claims 1 to 17, wherein the polyamide-polyolefin composite sheet is stretched as such. and/or deep-drawn sheet according to any one of claims 1 to 18. Procedural amendment (formality) September 27, 1980 Commissioner of the Japan Patent Office Case 1. Indication of 1982 Patent Application No. 80303
No. 2, Name of the invention Transparent shrinkable sheet consisting of a single layer or multiple layers 3, Person making the amendment 4, Sub-agent 6/Drawing to be amended 7, Contents of the amendment As shown in the attached sheet, however, engravings of the drawings (changes in content) none)

Claims (1)

[Claims] 1. A transparent shrinkable sheet consisting of a single layer or multiple layers, in which the layer, or in the case of multilayers, at least one layer also consists of polyamide, wherein the polyamide layer is made of linear polyamide and/or linear polyamide. a mixture of 85 to 10 wt. A transparent shrinkable sheet consisting of a single layer or multiple layers. 2. The polyamide layer is linear polyamide and/or linear copolyamide and/or elastomer boria 2
80 to 40% by weight of the component and 20 to 60% by weight of r and/or partially aromatic coboria.
The sheet according to claim 1, which is made of a mixture. 6. The sheet according to claim 1 or 2, wherein the partially aromatic boria compound is polyhexamethylene isophthalamide. 4. The sheet according to claim 1 or 2, wherein the partially aromatic boria iP is polytrimethylhexamethylene terephthalamide. 5. The sheet according to any one of claims 1 to 4, wherein the linear polyamide is polyamide 66. 6. The boria r layer is polyamide Y6640~60 weight-
A sheet according to any one of claims 1 to 5, consisting of a mixture of 20 to 50% by weight of a partially aromatic if IJ adduct and an amorphous linear copolyand of 20 to 30% by weight. . Z. The sheet according to any one of claims 1 to 6, wherein the elastomer component is a Zoroku copolymer consisting of linear polyamide segments and elastomer segments. 8. The sheet according to any one of claims 1 to 7, wherein the sheet is stretched at a temperature of 60 to 90°C. 9. The sheet according to any one of claims 1 to 8, which is stretched by a deep drawing method. 10. Claim 1 consisting of at least one polyamide layer and at least one polyolefin layer
The sheet according to any one of Items 1 to 10. 11. The sheet according to any one of claims 1 to 9, wherein the polyolefin layer is made of a polyolefin having a high shrinkage force Y. 12. The sheet according to any one of claims 1 to 11, wherein the polyolefin layer comprises an ethylene copolymer. 13. A sheet according to any one of claims 1 to 12, wherein the polyolefin layer consists of a mixture of various ethylene copolymers. 14. The sheet according to any one of claims 1 to 16, wherein the polyolefin layer is made of a low-density polyethylene type having a linear molecular structure Y. 15. Claim 1, wherein the polyolefin layer is comprised of a mixture of ethylene homopolymer and ethylene copolymer.
A sheet containing any one of items 1 to 14. 16. A sheet according to any one of claims 1 to 15, wherein the multiple layers are coextruded. 1Z Multiple layers glued together, claim t81
The sheet according to any one of Items 1 to 15. 18. The sheet according to any one of claims 1 to 17, wherein the polyamide V-polyolefin composite sheet itself is stretched and/or deep drawn.