DE2442226A1 - POLYAETHYLENE TEREPHTHALATE / TERPOLYMER BLEND - Google Patents

Description

The present invention relates to a composition of matter for the production of plates, foils or films, coatings, Vessels or containers or trays in the form of a mixture of polyethylene terephthalate (according to the following Definition) and a terpolymer of ethylene, vinyl ester and acrylic acid or methacrylic acid.

According to the conventional technique, unmodified polyethylene terephthalate is made used for the production of shaped and other objects, whereby its' toughness, malleability, Durability and being in chemical and. biological inert behavior can be exploited. Due to certain Properties or defects are unmodified. However, polyethylene terephthalate is unsuitable for some applications.

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F_24 ^ 5/2447-ß 2 4 A 2 2 2 6

Special polymer blends have therefore been developed which to meet certain requirements. For example, to improve the mechanical properties, such as hardness, impact resistance, toughness and abrasion resistance, Mixtures of polyethylene terephthalate with copolymers of cc-olefins and vinyl esters developed.

The subject of the invention is a composition of matter for plates, foils, coatings or containers in the form of a mixture of polyethylene terephthalate with a polymeric additive, which is mainly, but not entirely, derived from ethylene, which is characterized in that the mixture (based on weight ) 99 to 95 % polyethylene terephthalate and 1 to 5 % of a terpolymer of at least 65 % ethylene with (a) at least 5 % of a vinyl ester of a saturated aliphatic monocarboxylic acid having 1 to 6 carbon atoms and (b) 0.1 to 10 % acrylic acid and / or Includes methacrylic acid. The mixture preferably contains 5% terpolymer. Preferred vinyl esters are those saturated aliphatic monocarboxylic acids having 1 to 4 carbon atoms, especially vinyl acetate. The vinyl ester content of the terpolymer is preferably at least 12%, in particular 20 to> 0%. The preferred acrylic or methacrylic acid content of the terpolymer is 0.5 to 7%, in particular 0.5 to 3%. The most preferred terpolymer consists of 72 % ethylene, 27 % vinyl acetate and 1 % methacrylic acid.

It has been found that the polyethylene terephthalate / terpolymer mixtures according to the invention The plates or foils produced are particularly suitable for the production of thermoformed trays, which, for example, compared to trays made of unmodified Polyethylene terephthalate or polyethylene terephthalate containing conventional modifiers have higher toughness and less embrittlement or sagging after heating to temperatures up to about Tilt 200 ° C. Other advantages of using this

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Plates or films for thermoformed parts or trays appear, are the faster crystallization, which leads to a better porm resistance of the freshly manufactured objects, as well as an improved demoldability and better molding properties. It has also been found that tablets made from sheets or films made from such polyethylene terephthalate / terpolymer mixtures are shorter in the molding process in conventional vacuum thermoforming devices than trays made from sheets made from known mixtures or from unmodified polyethylene terephthalate Need molding time

A satisfactory, versatile tray is said to be cooking or baking its contents at temperatures Allow up to approx. 200 ° C, be thermally stable and do not become too brittle or fragile when heated or tend to form ice. Furthermore, it should not deform when heated. , - -.

So far, trays have been made from weldable polymers (such as vinyl and olefin polymers) to make it easier to attach lids to the trays. However, these polymers generally do not have the thermal resistance required for heating food. Already formed trays made of aluminum foil have also been used. B. is limited in that they are not suitable for microwave ovens.

It has been found that the compositions of matter according to the invention in the form of cooking or baking vessels or trays for packaging and subsequent cooking or baking as well Reheating of food can be used.

Terpolymefe which can be used according to the invention are, for example in U.S. Patent 3,215,678. According to the invention achievable extent of improvements in property

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shanks is apparently due to the change in the melt index of the terpolymer used according to the invention relatively little influenced.

Under the term "polyethylene terephthalate" as it applies to the Mixture according to the invention can be used include (a) polymers, with at least 97% of the polymer being the repeating Ethylene terephthalate units of the formula below:

contain, while the rest of lesser proportions of ester-forming Components, and (b) copolymers of ethylene terephthalate, in which up to 10 mol% of the copolymer of monomer units of z. B. diethylene glycol, propane-1,3-diol, Butane-1,4-diol, polytetramethylene glycol, polyethylene glycol, Polypropylene glycol or 1,4-hydroxymethylcyclohexane, which Monomer units in the copolymer production take the place of the glycol portion, and / or of z. B. Isophthalic, Bibenzoe, 1,4-naphthalene or 2,6-dicarbonic, adipic, sebacic or decane-1,10-dicarboxylic acid, which monomer units at take the place of the acid component in the production of copolymers, are formed

There are special restrictions on the comonomer content in With regard to the glass transition temperature of the polymer, since it has been found that copolymers with a glass transition temperature below about 50 ° C in general have poorer mechanical properties. This limit generally corresponds to an addition of comonomer of at most 10 mol%. An exception is in the case of the incorporation of bibenzoic acid, whereby the freezing temperature of the Copolymers is still above 50 ° C even if the

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Copolymers contains more than 10 mol% bibenzoic acid. The expert will readily recognize additional exceptions. The induction temperatures are the relevant characteristic values as determined by the standard methods of scanning differential calorimetry.

In the compositions of matter according to the invention that can Polyethylene terephthalate 0.1 to 1.5% by weight of a finely divided contain inert, mineral solids or a nucleating agent. Examples of suitable nucleating agents are Calcium carbonate, aluminum silicates and talc. The polyethylene terephthalate may contain a nucleating agent and an opacifying agent such as titanium dioxide as required. Preferably contains the polyethylene terephthalate 1% talc and 1.5% titanium dioxide. The inherent viscosity of the mixture is preferably 0.70 to 0.95 »for a product made therefrom" For the molded article, the inherent viscosity is preferably 0.65 to 0.85.

The inherent viscosity is determined here on a solution (polymer concentration 1 fo) in a mixture of 75% by weight of trifluoroacetic acid and 25% by weight of methylene dichloride at 30 ^° C. and is calculated as follows:

In

VVi

viscosity of the solution

Intrinsic viscosity = \ viscosity of the solvent; (inherent viscosity) C.

where C is the concentration in g of polymer / 100 ml of solution.

For the production of the compositions of matter according to the invention the ingredients should first be pre-dried at such temperatures and pressures that a maximum drying effect is achieved, but avoiding caking. The combination can be carried out by the regulated supply of the individual streams into a single or twin screw press, in which the components are melted and mixed

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will. The mixture mixed and melted in this way can then be extruded according to known methods.

Sheets (including cast, amorphous sheets) or foils from the mixtures according to the invention can be produced by known methods and in conventional devices ; see e.g. See U.S. Patent 2,823 4-21.

A wide variety of thermoforming processes and devices can be used, with one attached accordingly Foil (or plate) is drawn or pressed under vacuum into a mold, whereby the foil takes on the shape of the inner Surface assumes the shape with which it is brought into contact to produce the pressed object or vessel will. The processes include (1) vacuum suction processes, (2) stretch molding processes, (3) two-die presses, (4) Slip ring forming, (5) vacuum forming with die insert, (6) Compression molding with die insert, (7) shrinking on under vacuum, (8) corrugation process, (9) compression molding with enclosed Foil with contact heat and (10) compression molding with preheating and die insert.

Devices and details for such hot forming can be seen from DT-OS 2 408 183.

Table I shows the improvements made by the present invention.

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Table I.

materials

^ 'Minimum EntfοIm-T ₂ ") Forming ^ Forming time ^ ^; (sec.)

Before cooking
Tray Durability
(g-cm)

After cooking ι tray duration - (^ liability $ ■

A) Polyäthylenter ep hthalat

B) Mixture No. 1 *

C) Mixture No. 2 **

normal

normal

5 8

better than excellent

bad very bad

0.212 χ 10

2.32 χ 10

2.92

(1) The polyethylene terephthalate component of all materials contains 1 % talc and 1.5% titanium dioxide

slightly brittle

not brittle

not brittle / certain sagging
176.7 to 198.9 ⁰ C

No sticking when removing from the mold

Quickly adapts to the shape of the mold during hot forming Durability: tested according to ASTM test standard B-1707-62T 97% polyethyl ent erephthalate / 3 % terpolymer (72 % ethylene,

27% vinyl acetate and 1 % methacrylic acid)

93 _? 6 % polyethylene terephthalate / 6.4 % terpolymer (same as the blend above).

F_2445 / 2447-R! ' '2 A 4 2 226

The attached drawing is a graphic representation which enables a comparison of the impact strengths at different "internal viscosities" or " ^{inherent viscosities 1} * (inherent viscosities) of films (or plates), which on the one hand consist of a polyethylene terephthalate / terpolymer mixture according to the invention and on the other hand from a polyethylene terephthalate / cop olymer-Mi mixture were made.

The tested films from the PVC terephthalate / terpolymer range contain 96% polyethylene terephthalate and 3% of the terpolymer, which consists of 72 % ethylene, 27% vinyl acetate and 1 % methacrylic acid; the films from the polyethylene terephthalate / Cop olymer-Mi mixture contain 96 % polyethylene terephthalate and 3 % of the copolymer, which consists of 72% ethylene and 28% vinyl acetate. Both the polyethylene terephthalate / terpolymer mixture and the polyethylene terephthalate / copolymer mixture contain 1% talc.

To produce the test films, the polyethylene terephthalate / terpolymer mixture and the polyethylene terephthalate / copolymer mixture are extruded onto a cooled surface, after which the amorphous films produced in this way are peeled off from the surface. The films are subsequently contacted with a heated surface into contact and for 100 seconds at I5O ⁰ C for crystallization. After crystallization, the films are tested at room temperature with the aid of a Gardner impact strength tester. The test results are recorded in the graph, from which the improvements in impact strength brought about by the invention can be clearly seen.

The example below and Table II also show tablet shaping and tablet durability improvements, which the present invention achieves.

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example

Polyethylene terephthalate samples are mixed with a terpolymer of 72% ethylene, 27 % vinyl acetate and Λ% methacrylic acid and with Po lyäthyl ent he ephthal atp rob en, which were mixed with a copolymer of 72% ethylene and 28% vinyl acetate, with regard to the malleability toTabUßfcs and their

Compared to durability after oven heating. All samples contain 96 % polyethylene terephthalate, 3% of the terpolymer or copolymer and 1% talc (in each case% by weight, based on the total weight of the mixture).

The samples are made from carefully dried components, melt blended in a screw press and poured onto a cooled chill roll to produce amorphous foils. The amorphous films, which have a thickness of 325 to 450 η , are tested for their formability by preheating the film in question to 90 to 100 ° C. for 8 to 10 seconds and shaping it in a heated vacuum mold. The molding times and temperatures vary as shown in Table II.

The malleability or the quality of the form is checked, including the adaptation to the mold cavity * the evenness of the edge of the molded tray and the ease of removal from the mold; the results are shown in Table II.

The behavior of the molded tray in terms of toughness or fragility or brittleness (i.e. durability) is tested after 15 minutes of heating in the oven at 200 ° C; the results are also given in Table II.

In this durability test, the trays are heated with a Fingers tapped; as can be seen from Table II ', the Ta-' Bletts, which are made of sheets of mixed with the terpolymer

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-to-

Polyethylene terephthalate were made, "tough" and undamaged, while trays made of films made using the copolymer are so "brittle" that they break at the point of impact.

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Added Inherent - 0.71 τ shape abe 1 1 e II Hand- Trays oven Remarks £ tough Polymer * Viscosity 0.71 Malleability and Time, Durability of the " rule- Development heating, V / i bad abundance the 0.71 Fonntem Sec. cavity moderate- forraung **** Min «/ ⁰ C lung, brittle mixture temperature, customization * ¹ ability ** -JSi tough Terpolymer 0.78 ⁰ C 10 ■ 1.5 on -O
I. brittle Terpolymer 0.75 0.70 10 1 1 - Copolymer 0.77 170 10 1.5 2 2 good release * . 170 1.5 1 mung Terpolymer 0.78 170 8th 4th 1 15/200 Shape hanging cn
f-J Copolymer 0.77 8th 3 1 15/200 stay * Il '
CD Copolymer 0.77 '160 8th 2 3 1.5 15/200 Shape hanging CO Terpolymer 0.81 160 8th 3 1 1.5 - stay O 160 3 1 good “Ent for - » Copolymer • 0.81 155 8th. 1 1 - mung - * ι
cn - 3 - Copolymer 0.83 155 8th 2 2 brittle, yellow Jpf I. 3 unequal- -C ^ I. Terpolymer 0.76 150 8th 3 1.5 - siger, thinner ¹ ^ 1 Spot ¹ ^
ro Copolymer 150 8th 1 1.5 - gut.e Entfor- cd Copolymer 8th 1 1 15/200 mung Copolymer 150 8th 1 1 1.5 15/200 150 1 2 150 2 Terpolymer 6th 1 - 1 150 ' 1

Table II (continued)

Added Inherent Formtem - Form - Cavity -. Edge Ent Oven Remarks

Polymeres * Viscosity temperature, time, adjustment ** rule formation *** heating, * P

the ⁰ C sec. massive- min./ ⁰ 0 i \)

Mix ■ ability ** E

Copolymer 0.71 150 6 1 1 3 - shape-hanging- j £

stay ;§

Terpolymer 0.70 150 6 1 1 1 15/200 tough w

Copolymer 0.71150 6 1 1 3 15/200 brittle,

yellow

... * cn terpolymer of 72 wt% _- ethylene, 27 wt% vinyl acetate and 1 wt% of methacrylic acid;
° Copolymer of 72% by weight of ethylene and 28% by weight of vinyl acetate.

öd * * Form quality

ο 1 - flawless

^ i 2 - good

- * _λ 3 - relatively good to bad

~ * ro 4 - insufficient

ίο '* ♦ * Demolding

1 - good demolding, no press burr

2 - good demolding, little press burr

3 - poor demoulding, a lot of press burr

Claims (17)

Claims 1. Substance composition for plates, foils, coatings or containers in the form of a mixture of polyethylene terephthalate with a terpolymer additive, which is mainly, but not entirely, derived from ethylene and also from vinyl esters and unsaturated carboxylic acids, such as acrylic acid, characterized in that the mixture (based on weight) 99 to 95 % polyethylene terephthalate and 1 to 5 % of a terpolymer of at least 65 % ethylene with (a) at least 5 % of a vinyl ester of a saturated aliphatic monocarboxylic acid having 1 to 6 carbon atoms and (b) 0.1 to 10 % Acrylic acid and / or methacrylic acid. 2. Composition according to Claim 1, characterized in that that a vinyl ester of an acid with 1 to 4 carbon atoms is used. 3. Composition according to claim 2, characterized in that that the ester is vinyl acetate *. 4. Composition according to claim 1 to 3, characterized in that the vinyl ester content is at least 12 % . 5. Composition according to claim 4-, characterized in that the vinyl ester content is 20 to 30 % . 6 “Composition according to Claims 1 to 5”, characterized in that the proportion of acrylic and / or methacrylic acid is at least 0.5 % . 7. Composition according to claim 1 to 6, characterized in that the proportion of acrylic and / or methacrylic acid up to 7%. . - 13 - 50981-0 / 1152 F-2445/1447-R ^ _m 8. The composition according to claim 6, characterized in that the proportion of acrylic and / or methacrylic acid is up to to 3%. 9- Composition according to claim 1 to 8, characterized in that the proportion of terpolymer is 3 % . 10. Composition according to claim 1 to 3 »characterized in that the terpolymer consists of 72% ethylene, 27 % vinyl acetate and 1% methacrylic acid. 11. Composition according to claim 1 to 10, characterized in that that the polyethylene terephthalate 0.1 to 1.5 wt.% Of a finely divided inert, mineral Contains solid matter. 12. Composition according to claim 1 to 11, characterized in that that the polyethylene terephthalate is a nucleating agent contains. 13 · Composition according to claim 12, characterized in that the nucleating agent is calcium carbonate Is aluminum silicate or talc. 14. Composition according to claim 1 to 12, characterized in that that the polyethylene terephthalate contains an opacifier. 15- composition according to claim 1 to 14, characterized in that that the polyethylene terephthalate contains titanium dioxide. 16. Composition according to claim 1 to 15 »characterized in that the polyethylene terephthalate contains 1 % talc and 1.5 % titanium dioxide. _ 14 __ 509810/1152 17. Composition according to claim 1 Ms 16, characterized in that the inherent viscosity the mixture is 0.70 to 0.95. 509810/1 152 Blank page