DE3240742A1 - QUICK CRYSTALIZING, ANTIMONOXIDE CONTAINING POLYETHYLENE TEREPHTHALATE - Google Patents

Description

Are polyethylene terephthalate homopolymers and copolymers characterized by excellent physical properties. These materials are of great interest to the use for the production of films and fibers and they are also suitable as molding materials. Be in these crowds often reinforcement materials, such as glass fibers, are incorporated to improve the mechanical properties of the polyethylene terephthalate to improve manufactured products.

However, it has been found that the relatively slow rate of crystallization of polyethylene terephthalate, the use of such polyester compositions in the injection molding process is strong restricts. Efforts are therefore still needed to find new promoters that increase the rate of crystallization accelerate the discovery of polyethylene terephthalate and its copolymers. Of the various patents that the Relate to acceleration of polyethylene terephthalate and describe efforts to address these disadvantages of polyesters eliminate, should be mentioned: US-PS

3,673,139; 4,098,845; 4,107,149; and 4,136,089. Furthermore can be applied to GB-PS 1,505,599 and DE-PS 2,545,720; 2,653,120; 2.7O6 ».123; 2,706,124 and 2,706,128 to get expelled. As can be seen from these references, these efforts to date have focused on Development of special additives or promoters that reduce the crystallization rates of polyethylene terephthalate homopolymers and copolymers accelerate. The requirements for injection molding processes and the economic factors involved in this technical field are such that

further research in this area is needed.

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According to the invention it was found that the

Crystallization Rate of Polyethylene Terephthalate Homopolymers and copolymers as sol before, as well as from these Polyester-containing compositions can be improved by adding antimony oxide. The addition of antimony oxide too Polyethylene terephthalate materials give a quick crystallizable polyethylene terephthalate, which is very good is suitable for injection molding processes.

The masses * which antimony oxide, glass fibers and Containing polyethylene terephthalate material can according to methods known to those skilled in the art can be prepared. It has been found, however, that it is most convenient to dry mix the materials and extrude the resulting mixture to compound the mass well and to tablet. It has been found to be advantageous to mix the molding compound in two or more than one stage to carry out several stages.

According to the invention it has been found that antimony oxide is an effective promoter of the crystallization rate of polyethylene terephthalate and its homo- and copolymers, so that polyethylene terephthalate can be used in a wider range of application conditions. The antimony oxide can be added to the polyethylene terephthalate in concentrations from about 0.05 or 0.1 to about 40.0 percent by weight of the polyethylene terephthalate. However, it is preferably added in amounts of from about 2 to about 10 %.

The antimony oxide can be added as such to a polyethylene composition. To achieve the best results, however, it has proven advantageous to prepare a concentrate of 5 % antimony oxide and polyethylene terephthalate and to add the concentrate to the polyethylene terephthalate compositions in the amount calculated for the desired concentration in the finished mixture.

In general practice in carrying out the invention, the components are extruded mixed (compounded). However, other measures for mixing the Ingredients which are also encompassed by the present invention.

The present examples serve only to illustrate the invention and do not represent any restriction same represents.

Example 1:

5 parts of antimony oxide and 95 parts of polyethylene terephthalate were dry mixed and the obtained one Mixture was at a melting temperature of 270-300 ° C extruded to be compounded and tabletted.

Parts of the concentrate obtained were dry-blended with further amounts of polyethylene terephthalate and at 270 - 300 ⁰ C extruded melt temperature, wherein a Antimonoxidkonzentrat, based on the total composition as shown in Table 1 was obtained. These samples are identified in the table as the concentrate add-on method.

Other mixtures of Antimo.noxid with polyethylene terephthalate as shown in Table 1, relating to the Gesämtzusammensetzung concentrations were determined by dry quenching and subsequent extrusion at a melt temperature of 270 - 300 ⁰ C prepared. These samples are referred to in the table as the direct addition method. .

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Table I.

Additional method

Sample no. PET g Sb ₂ O ₃ g Sb ₂ O ₃ - Direct concentrate DSC AT ⁰ C 1 1400 600 30% X 35 2 1200 800 40 % X 33 3 1980 20th 1.0 % X 39 4th 1900 100 5.0 % X 37 5 1600 400 20th % X 33 6th 1800 200 10.0 % X 35 7th 999 1 0.1 % X 53 8th 998 2 0 _s 2 % X 47 9 997 3 0.3 % X 45 10 995 5 0.5 % X 48 η 992 8th 0.8 « X 41

In the slow DSC test recorded in Table I (Differential Scanning Colorimetry-Differential Scanning Colorimetry), resin disks are cut off from at least two shaped cubes to a sample weight of 5 mm. The samples are placed in an aluminum crucible and pressed into place. The crucible is heated under nitrogen from room temperature to 285-29O ⁰ C at a rate of 40 ° C / min. The temperature is held for 5 minutes at 29o ⁰ C and the aluminum pan pressed to ensure contact to ensure good material. Then, it was cooled at 20 ° C / min to 5O ⁰ C or less. The sample is then heated from room temperature at 20 ° C./min to the melting point under nitrogen. As soon as the baseline has been obtained again, cooling is started at 20 ° C / min. The melting and freezing point curves are recorded.

ΔΤ is the difference between the melting and freezing points of the DSC thermogram. A low Δτ value indicates a rapid rate of crystallization. A ΔΤ less than 60 is usually considered to be indicative of good shape properties. A more detailed consideration of the use of differential scanning colorimetry in determining the crystallization properties of polyethylene terephthalate is given in the treatise "Influence of Branched Codiols on the Crystallization Behavior of Aromatic Polyesters"; P. Bier et al .; Applied Macromolecular Chemistry 65; No. 1005; 1977; Pages 1 -21, especially pages 5-12, can be found. Example 2:

A molding compound consisting of 60 % polyethylene terephthalate, 30% glass fiber and 10 % antimony oxide was produced by dry mixing these constituents and extruding the resulting mixtures at a melting temperature of ^{270-30O 0 C.}

The resulting mass was injection molded into test bars of 127 × 12.7 × 3.17 mm. The test bars obtained in this way were characterized by flat, smooth surfaces, in contrast to control bars made from compositions which did not contain any antimony oxide, which had discarded, rough surfaces.

Claims (5)

Claims; 1. Composition j, characterized in that it consists of polyethylene terephthalate and antimony oxide, the antimony oxide content, preferably about 0.05 to about hO% . based on the polyethylene terephthalate. 2. Composition according to claim 1 _s, characterized in that the antimony oxide is present in an amount of about 2 _f 0 to about 10%. 3. Composition according to claim 1 or 2, characterized in that that it still contains glass fibers. k. "Process" for the preparation of a composition, characterized in that, in a first stage, part of the polyethylene terephthalate is mixed with antimony oxide and the remainder of the polyethylene terephthalate is added to the mixture obtained in a second stage. 5. Process for the preparation of compositions according to claim 4, characterized in that in a first Stage mixing part of the polyethylene terephthalate with antimony oxide and the remainder of the polyethylene terephthalate obtained Mix in two or more subsequent additives.