MXPA01005490A - Moulding substances based on poly-c2-6 - Google Patents

Abstract

Glycerol fatty acid esters of C12-24-fatty acids which may have 1 hydroxyl group and 1 to 3 C-C-double bonds are used as an additive in poly-C2-6-alkylene terephtalate-based moulding substances. The thermoplastic moulding substance contains the following in relation to the sum of the components A and B and optionally, C to E, which make up 100 wt.%overall:a) 40 to 99.99 wt.%of at least one poly-C2-26-alkylene terephthalate-based polyester as component A;b) 0.01 to 3 wt.%glycerol fatty acid esters of C12-24-fatty acids which may have 1 hydroxyl group and 1 to 3 C-C-double bonds as component B;c) 0-49.99 wt.%blend polymers which are miscible with or dispersible in component A as component C;d) 0 to 50 wt.%fillers as component D;and e) 0 to 10 wt.%other usual additives as component E.

Description

MOLDING SUBSTANCES BASED ON C2-C6 POLYALYKYLENE TEREPHTHALATE The invention relates to molding compositions based on C2-C6 polyalkylene terephthalates and comprises mold release agents, and also to the use of some mold release agents in molding compositions. Polybutylene terephthalate and polybutylene terephthalate combinations are widely processed by extrusion or injection molding to form molds, which are used in a variety of consumables in the household, food and beverage and medical sectors. To produce the molds, additives are usually added to the polybutylene terephthalate to give good demolding performance, that is to allow short cycles of time and prevent the formation of mold deposits. The additive here should not change the other aspects of the performance of polybutylene terephthalate. When plastics are used in the food and beverage sector or the doctor, the transfer of substances from the plastic to the food inside the body has to be prevented. Regarding this, there are, for example, specifications from the Food and Drug Administration (FDA) in the United States and from the BGA (Federal Health Council of Germany) in Germany.

It is an object of the present invention to provide thermoplastic molding compositions based on C2-C6 polyalkylene terephthalates and comprising a mold release agent which is not hazardous to health and which, in particular, has low volatility in the composition of molding It has been found that this object is achieved by using glycerol fatty acid esters of C 2 -C 24 fatty acids which may have a hydroxyl group and 1 to 3 carbon-carbon double bonds as an additive for molding compositions based on C2-C6 polyalkylene terephthalates. They are used in particular as mold release agents. The fatty acid esters of glycerol can be mono-, bis- or triesters. Preferably they are esters of bis (fatty acid) glycerol. The fatty acids herein are derived from C 2 -C 24 fatty acids, preferably C 4 -C 20 fatty acids, in particular C 6 -C 8 fatty acids, which may have a hydroxyl group and from 1 to 3 carbon-carbon double bonds. carbon. Preferably they have zero, one or two carbon-carbon double bonds. If they have a hydroxyl group, they preferably also have one or two carbon-carbon double bonds. The fatty acid radicals are generally linear. Examples of fatty acids that can be used in the fatty acid esters of glycerol are stearic acid, linoleic acid, linolenic acid, oleic acid, palmitic acid, castor oil fatty acid and nonanoic acid. Other suitable fatty acids are known to the skilled worker. The glycerol fatty acid esters herein can be prepared by known processes. The glycerol bis stearate is used in particular as a mold release agent. This compound is available, for example, from Henkel under the tradename Loxiol® VPG 1206. The glycerol fatty acid esters and the glycerol bistearates used according to the invention meet the requirements placed on the compounds which can be contacted with the food or with the human body. Glycerol bistearates have previously been used primarily to extrusion and injection molding polymers such as PVC, which can be processed at relatively low temperatures, below 220 ° C. The reason for this is that glycerol bis stearates are increasingly volatile at higher temperatures. For example, a thermogravimetric analysis of a glycerol bistearate shows a marked weight loss from about 220 ° C. In the range of 250 to 270 ° C, the temperature to process polybutylene terephthalate and combinations of polybutylene terephthalate, the measured weight loss is up to 5% (from 40 to 340 ° C, 10 ° C / min) . The mold release agents used hitherto for polybutylene terephthalate have therefore been those such as fully esterified pentaerythritols., which have marked lower volatility under these conditions. For example, the weight loss for a fully esterified pentaerythritol at 270 ° C is less than 1% (from 40 to 340 ° C, 10 ° C / min). According to the invention, it has been found that the mixtures of the aforementioned glycerol fatty acid esters, in particular of glycerol bis stearate, with polybutylene terephthalate are significantly less volatile in a mold release agent than the volatiles than the compounds Separate would suggest. Without joining any particular theory, this may be due to the fact that the ester on the surface of a mold has a sufficiently good degree of binding to polybutylene terephthalate. The properties of polybutylene terephthalate with the additive of glycerol bis stearate are not different from the properties of a polymer with additives that are known mold release agents for polybutylene terephthalate. This is shown by thermogravimetric measurements and by studies on demolition performance and on the formation of deposits in molds at a processing temperature of 260 ° C, and also by studies on long-term migration (11 days / 150 ° C). There is also no adverse effect on other aspects of performance, such as mechanical and thermal rheological properties. The mixtures made of the glycerol fatty acid esters used according to the invention and the molding compositions based on C2-C6 polyalguylene terephthalates can be used universally, or in non-reinforced or otherwise reinforced molding compositions. The molding compositions herein are based on C2-C6 polyalkylene t-erephthalates. These may be C2-C6 polyalkylene terephthalates or polymer combinations made therefrom. They may be in particular polybutylene terephthalates or combinations of polybutylene terephthalate. The invention also provides a thermoplastic molding composition comprising, based on the total components of ^ and B and, if present, C to E, which together give 100% by weight, a) as component A from 40 to 99.99% by weight of at least one polyester based polyalkylene terephthalate C ^ -Ceb) as component B, from 0.01 to 3% by weight of fatty acid esters of glycerol of C? 2- C24 fatty acids that can have a hydroxyl group and of 1 to 3 carbon-carbon double bonds , c) as component C, from 0 to 49.99% by weight of combined polymers miscible with component A or dispersible therein. d) as component D, from 0 to 50% by weight of fillers, and e) as component E, from 0 to 10% by weight of other usual additives.

Component A The novel molding composition comprises, as component A, from 40 to 99.99% by weight of a polyester based on C2-C6 polyalkylene terephthalates. Polymers of this type are known per se. The polyesters can be prepared by reacting terephthalic acid, its esters or other ester-forming derivatives with 1,4-butanediol, 1,3-propanediol or, respectively, 1,2-ethanediol in a manner known per se. Up to 20 mol% terephthalic acid can be replaced by other bicarboxylic acids. Examples of these which may be mentioned are naphthalenedicarboxylic acids, isophthalic acid, adipic acid, acelaic acid, cebasic acid, dodecandioic acid and cyclohexanedicarboxylic acids, mixtures of these carboxylic acids and ester-forming derivatives thereof. It is also possible to replace up to 20 mole% of the dihydroxy 1,4-butanediol, 1,3-propanediol and 1,2-ethanediol compounds by other dihydroxy compounds, such as 1,6-hexanediol, 1-hexanediol, 1, -cyclohexanediol, 1,4-di (hydroxymethyl) cyclohexane, bisphenol A, neopentyl glycol, mixtures of these diols or ester-forming derivatives thereof. Preferred aromatic polyesters are polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT) and in particular polybutylene terephthalate (PBT), which have been formed exclusively from terephthalic acid and the corresponding diols. Some or all of the aromatic polyesters may also be in the form of recycled polyester materials, such as PET regrind made from bottle material or waste from bottle production.

Component B The glycerol fatty acid esters used according to the invention as component B have been described above. The amount in which they are used is 0.01 to 3% by weight, preferably 0.2 to 1.5 or by weight, preferably particularly 0.2 to 1.0% by weight.

Component C The molding compositions may comprise, as component C, from 0 to 49.99% by weight, preferably from 0 to 40% by weight, particularly preferably from 0 to 30% by weight, of combined polymers miscible with component A or dispersible in the same. These can, for example, be conventional rubbers (inserted). In particular, grafted copolymers which may have been constructed from C1-C10 alkyl acrylates as the graft base and conventional ethylenically unsaturated monomers as a graft may be used.

Examples of these are: Ethylene-vinyl acetate rubbers, silicone rubbers, polyether rubbers, hydrogenated diene rubbers, polyalkanemer rubbers, acrylate rubbers, ethylene-propylene rubbers, ethylene-propylene-diene rubbers, rubbers. of butyl, methyl methacrylate-butadiene-erythrene (MBS) rubbers and methyl methacrylate-butyl-styrene-acrylate rubbers, so long as these are miscible with component A and / or dispersible therein. Preference is given to using acrylate rubber, ethylene-propylene rubber (EP), ethylene-propylene-diene rubber (EPDM). Other possible materials are miscible polymers or copolymers, such as polycarbonates, polymethacrylates, in particular PMMA, polyphenylene ethers or syndiotactic polystyrene. It is also possible to use reactive rubbers which are bonded to the polyester (component A) by means of a covalent bond, for example particulate acrylate rubbers and / or polyolefin rubbers grafted with anhydrides, such as maleic anhydride, or with epoxy compounds, such as glycidyl methacrylate. Finally, it is also possible to use one or more grafted copolymers made of PBT and PSAN or to use segmented copolymers, such as block copolymers or multiblock copolymers made from at least one segment of PBT with M >.; 1000 and of at least one segment of PSAN or of a PSAN-compatible / miscible segment with Mw > 1000. The last mentioned polymers can also improve the binding to other combined polymers, for example to copolymers based on aromatic vinyl monomers and acrylonitrile and / or methacrylonitrile. Possible combined components of this type are (α-methyl) styrene / methacrylonitrile.

Component Q The fillers used as component D may be present in amounts of 0 to 50% by weight. These are preferably commercially available glass fibers. These generally have an average length of 0.1 to 0.5 mm, preferably 0.1 to 0.4 mm, and a diameter of 6 to 20 μm. Particular preference is given to glass fibers made of glass E. To improve adhesion, the glass fibers may have been coated with organosilanes, epoxysilanes or other polymer coatings.

Component E The novel molding compositions may comprise, as component E, from 0 to 10% by weight, preferably from 0 to 7.5% by weight, preferably particularly from 0 to 5% by weight, or other conventional additives. Examples of additives of this type are: UV stabilizers, oxidation retarders, dyes, pigments, dyes, nucleating agents, antistatics, antioxidants, stabilizers to improve thermal stability, to increase light stability or to increase resistance to hydrolysis and resistance to chemicals, agents for preventing heat decomposition, and in particular, in addition to the mold release agents used according to the invention, lubricants useful for producing molds. These other additives may be fed at any stage of the preparation process, but preferably at an early time to make use at an early stage of the stabilizing effects (or other specific effects) of the additive. Heat stabilizers or oxidation retarders are usually metal halides (chlorides, bromides or iodides) derived from the metals of group I of the Periodic Table of the Elements (for example Li, Na, K, or Cu). Suitable stabilizers are blocked normal phenols, or in addition vitamin E or compounds of similar structure. HALS stabilizers (Obstructed Amine Light Stabilizers) are also suitable, such as benzophenones, resorcinols, salicylates, benzotriazoles and other compounds (for example Irganox®, Tinuvin®, such as Tinuvin® 770 (HALS absorber, bis (2, 2, 6,6-tetramethyl-4-piperidyl) sebacate) or Tinuvin® P (UV absorber - (2H-benzotriazol-2-yl) -4-methylphenol) or Topanol®). The amounts of these normally used are up to 2% by weight, based on the complete mixture. Other possible additives are silicone oils, oligomeric isobutylene or similar substances, usually in amounts of 0.05 to 5% by weight. Pigments, dyes, color brighteners, such as ultramarine blue, phthalocyanines, titanium dioxide, cadmium sulfides and perilentetracarboxylic acid derivatives can also be used. Another additive that can be used is carbon black, pure or as a master batch. The amounts used of processing aids and stabilizers, such as UV stabilizers, lubricants and antistatics, are usually from 0.01 to 5% by weight, based on the complete molding composition. It is also possible to use amounts of, for example, up to 5% by weight, based on the complete molding composition, of nucleating agents, such as talc, calcium fluoride, sodium phenylphosphinate, alumina or finely divided polytetrafluoroethylene. Amounts of up to 5% by weight, based on the molding compositions, plasticizers such as dioctyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, hydrocarbon oils, N- (n-butyl) benzenesulfonamide, or o- or p- toluene-ethylsulphonamide are advantageously added. It is also possible to add amounts of up to about 5% by weight, based on the molding composition, of dyes, such as dyes and pigments. Components A, B and, if desired, C to E can be mixed in any desired manner using any of the known methods. The components A-E can be mixed as such or in addition in the form of mixtures of a component with one or more # of the other components. For example, novel thermoplastic molding compositions can be prepared by mixing component A with each of components B and C or with a mixture made therefrom., and with the component E if desired, by melting the product in an extruder and feeding the glass fibers D by means of an entrance in the extruder. The novel molding compositions can be processed by known methods of thermoplastic processing to form molds. In particular, these can be produced by thermoforming, extrusion, injection molding, calendering, blow molding, compression molding, pressure sintering, thermoforming or sintering, preferably by injection molding. The present invention also provides the molds that can be produced from the new molding compositions. The thermoplastic molding compositions can be used to produce molds, fibers or films. These molds are preferably derived from the domestic, food and beverage or medical sectors. In the domestic sector they can be used, for example, for parts of deep fat fryers, such as parts for lids and handles, and in the health sector for toothbrush heads or brushes, for example. The novel thermoplastic molding compositions are also suitable for other molds used in the domestic sector, preferably in the kitchen sector. These include bread baking equipment, toasters, tabletop racks, kitchen equipment, electric can openers and juicers. In these articles, novel molding compositions are preferably used to produce switches, housings, handles or lids. The novel molding compositions can also be used for molds in stoves, where particular preference is given to stove handles, stove knobs and switches. The novel molding compositions can also be used in molds that meet the requirements of the federal drug administration or equivalent national authorities in other countries. In this sector, particular preference is given to the packaging of medicines and to the outer packaging of medical equipment. The novel molding compositions can also be used in the food and beverage packaging sector. Preference is given here to boxes, jars, plates and containers of other types, all of which are molds made from the novel molding compositions. In the context of applications for novel molding compositions particular emphasis should be given to their compatibility with food and their resistance to fats and liquid, which is particularly useful in parts of household equipment. The use of the glycerol bis stearates defined above has proven to be particularly successful in molding compositions to produce molds that can be exposed to high temperatures. Particular molds of this type are parts of lanterns used in the area of the lantern, in which temperatures may occur above 100 ° C, preferably 110 ° C and preferably particularly 130 ° C and up to a maximum of 200 ° C when the Fanal is operating. Parts of this type can be reinforced with fiberglass or otherwise not reinforced with glass fibers. The preferred fanal parts are fanal frames. The particular use of the aforementioned glycerol bis stearates to produce parts of a fanal is that in the parts of the fan of this type with a reflecting surface it does not occur that these surfaces are matted. In addition, when the glycerol bis stearates defined above are used, even after a relatively long period of operation of the lamp there are no deposits on the transparent areas of the lamp that transmit light, and the metallized surfaces of these molds retain their reflecting properties. The use of the glycerol bis stearates defined above also makes it possible to achieve the other advantageous properties, for example low cycle times, without formation of mold deposition during injection molding, and excellent quality of metallized surfaces. In particular, no haze is observed on the metallized surface as a result of any uncontrolled migration of the mold release agent when the mold is heated to 100-200 ° C, preferably 110-180 ° C and particularly preferably 130-? 70 ° C and it is therefore possible to obtain molds with surfaces that have long-lasting reflecting properties when metallized. The use of the glycerol bisystearates defined above has also proved successful in the production of large surface area molds that are comparatively thin in relation to their surface area and for which excellent demolding performance is necessary. Particular large surface area molds of this type are cross members of sliding roofs, bodywork parts, air intake grilles, instrument panel parts, such as instrument panel mounts, covers, air ducts, parts for add, particularly for the center console, as a part of the glove compartment, and protective contours for tachometers. Other possible applications are in the medical technology sector. The novel molding compositions can also be used in any of the other known applications for polybutylene terephthalate that do not require compatibility with food and with the human body. The invention will be described in greater detail in the following examples. Examples For preparing the molding compositions, polybutylene terephthalate (PBT) with a viscosity number was used.

(VN) of 130. In the reference compositions, a fully esterified pentaerythritol was used as the mold release agent, and in the novel molding compositions glycerol bis stearate was used. Glass fibers were used in some of the compositions. The mechanical properties were determined as follows: Impact resistance was determined for ISO 179 / leU. The impact strength of the notch was determined for ISO 179 / leA. The modulus of elasticity for ISO 527-2 was determined. The elastic limit for ISO 527-2 was determined. The elongation at break was determined for ISO 527-2. The results are listed in the following Tables.

Table 2: DIN / ISO tests *) Melting temperature / mold surface ++) Detectable deposit = -, not detectable = + NB No fracture

Claims (7)

1. The use of glycerol bis (fatty acid) esters of C12-C2 fatty acids, wherein the fatty acids may have a hydroxyl group and from 1 to 3 carbon-carbon double bonds, as an additive for molding compositions based on terephthalates of polyalkylene of C2-C- ß •

2. The use as claimed in claim 1, as a mold release agent.

3. The use as claimed in claim 1 or 2, wherein the fatty acid esters of glycerol are derived from Ci4-C2o-4 fatty acids. The use as claimed in any of claims 1 to 3, in wherein the molding compositions are based on polybutylene terephthalate compositions. 5. A thermoplastic molding composition comprising, based on the total of components A and B and, if present, C to E, which together give 100% by weight, a) as component A, from 40 to 99.99% by weight of at least one polyester based on C2-C6 polyalkylene terephthalates, b) as component B, from 0.01 to 3% by weight of bis (fatty acid) esters of glycerol of C12-C24 fatty acids, wherein the fatty acids can have a hydroxyl group and from 1 to 3 carbon-carbon double bonds, c) as component C, from 0 to 49.99% by weight of combined polymers miscible with component A or dispersible therein, d) as a component D, from 0 to 50% by weight of fillers, and e) as component E, from 0 to 10% by weight of other usual additives. 6. The thermoplastic molding composition as claimed in claim 5, wherein component A is polybutylene terephthalate. 7. The process for preparing thermoplastic molding compositions as claimed in claim 5 or 6, by mixing the components. 8. The use of thermoplastic molding compositions as claimed in claim 5 or 6, to produce molds, fibers or films. 9. The mold, a fiber or a film made from a thermoplastic molding composition as claimed in claim 5 or 6.