NO832187L - OXYBENZOYL POLYESTER COMPOSITIONS CONTAINING TALKS FOR USE IN OVEN USE OBJECTS - Google Patents

Description

It is known that certain plastics have found some use for the manufacture of ovenware or so-called fire-

solid barrels. E.g. polymethylpentene has been used for injection-molded troughs or forms that can be used for the production

ling of different foods. Polysulfone has also been used in connection with foodstuffs. However, no satisfactory material has been found that can be used within the highly varying area with regard to conditions and requirements set in connection with refractory barrels,

forms and the like, which can be used either in normal heat-

ovens or in microwave ovens.

In addition to the fact that the material must of course withstand the temperatures

trips that occur in the device used for roasting or cooking, the material must also have a unique combination of a number of other properties before fireproof dishes and forms that can be used for the production of food can be produced from said material. The material must therefore have good electrical properties. It must be able to withstand severe temperature shocks in that refractory barrels or molds made from the material must be able to go from conditions of extreme cold to high temperatures within a relatively short period of time. The material must also have good hardness and impact strength and have high tensile strength and bending strength.

It must also be able to withstand boiling water, the necessary acids

appear in the food and fat, besides that it must be able to withstand immersion in different washing solutions.

In connection with the production of different types of food

the refractory dishes or forms made from the material must not be colored by different types of food. Furthermore, the material must have a non-stick surface so that the food products produced in neurite dishes or forms can be easily released from them. The material must also not emit any volatile compounds and must not have any extractable components.

In addition to fulfilling all the aforementioned requirements, artik-

clay produced from the material has a satisfactory appearance which means that the articles can be easily marketed.

important information

For archival reasons, the Norwegian Patent Office only has access to documents for this generally available patent application that contain handwritten notes, comments or crossing outs, or that may be stamped "Expired" or the like. We have therefore had to use these documents for scanning to create an electronic edition.

Handwritten remarks or comments have been part of the proceedings, and must not be used to interpret the content of the document.

Cross-outs and stampings with "Expired" etc. indicates that newer documents have been received during the proceedings to replace the earlier document. Such crossing out or stamping must not be understood as meaning that the relevant part of the document does not apply.

Please ignore handwritten remarks, comments or crossing outs, as well as any stamps with "Expired" etc. which have the same meaning.

Bakeware items or refractory dishes or forms that fulfill

ler the above-mentioned requirements are provided according to the present invention by said articles being produced from a plastic material based on fully aromatic polyesters, then more particularly on oxybenzoyl polyesters.

The fully aromatic polyesters used in accordance with the present invention consist of a combination of repeating units with one or more of the following formulas: where x is 0, S,

NH or SO2 and n is 0 or 1, and

where the sum of the number p + q + r + s + t + uide groups present varies from approx. 3 to approx. 800.

Combinations of the above units include a union of the carbonyl group of formulas I, II, IV and V and the oxy group of formulas I, III, IV and VI. In the most general combination, all units with the above formulas will be present in a single copolymer. The simplest embodiment is homopolymers of units I or IV. Other combinations include mixtures of units II and III, II and VI, III and V, V and VI, and I and IV.

The location of the functional groups is preferably in the para positions (1,4). Said groups can also be placed in the ortho(1,2) position in relation to each other. With respect to the naphthalene group, the most advantageous and desirable placement of the functional groups is 1,4, 1,5 or 2,6. Such groups can also be in an ortho position in relation to each other.

The symbols p, q, r, s, t and u are numbers and indicate the number of groups present in the polymer. The grand total of p + q +

r + s + t + u can vary from 3 to 800, and the ratio q/r,

q/u, t/r, t/u, q + t/r, q + t/r + u and t/r + u can vary from approx. 10/11 to approx. 11/10 and the most beneficial ratio is 10/10.

Examples of compounds from which groups of formula I can be obtained are p-hydroxybenzoic acid and its esters such as phenyl-p-hydroxybenzoate, p-acetoxybenzoic acid and isobutyl-p-acetoxybenzoate. Groups of formula II can be derived from terephthalic acid, isophthalic acid, diphenyl terephthalate, diethyl isophthalate, methyl ethyl terephthalate and the isobutyl half-ester of terephthalic acid. Groups of formula II may be derived from compounds such as p,p'-biphenol; 4,4<1->dihydroxybenzophenone, resorcinol and hydroquinone. Such compounds can also be used for supplying groups with the formulas VI - VIII.

Examples of monomers represented by formula IV are 2-hydroxy-6-naphthoic acid, 6-hydroxy-1-naphthoic acid, 5-acetoxy-1-naphthoic acid and phenyl-5-hydroxy-1-naphthoate. Monomers of formula V include 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid. The diphenyl esters or dicarbonyl chlorides of these acids can also be used. Examples of monomers of formula VI are 1,4-dihydroxynaphthalene; 2,6-diacetoxynaphthalene and 1,5-dihydroxynaphthalene.

Particularly preferred for use in the present invention

are plastics based on oxybenzoyl polyesters.

A preferred group of oxybenzoyl polyesters are copolyesters with repeating units of formulas VIII and IX.

where x is -0 or -SG^-; m is 0 or 1; n is 0 or 1; q:r is 10:15 to 15:10; p:q is 1:100 to 100:1; p + q + r = from 3 to 600, preferably between 20 and 200. The carbonyl groups in the group of formula I or III are bonded to the oxy groups in a group of formula I or IV; and the oxy groups in the group of formula I or IV are bound to the carbonyl groups in the group of formula I or III.

Other groups of aromatic polyesters that can be used are aromatic polyesters containing repeating units with the 2,6-dicarboxynaphthalene group and/or the p-oxybenzoyl group and the symmetrical dioxyaryl group and variations thereof. Such polyesters are described in US patents no. 4,067,852, 4,083,829, 4,130,545, 4,161,470, 4,184,996, 4,219,461, 4,224,433, 4,238,598, 4,238,599, 4,256,624, 4,266 .802, 4,279,803, 4,318,841 and 4,318,842.

The preferred copolyesters are those with repeating units of formula X:

The synthesis of such polyesters is described in detail in US Patent No. 3,637,595 entitled "P-Oxybenzoyl Copolymers", and this patent is incorporated herein by reference.

Polyesters that can be used in the present invention can

also chemically modified in different ways, by e.g. in the polyester include monofunctional reactants such as benzoic acid or tri- or higher functional reactants such as trimesic acid. The benzene rings in such polyesters are preferably unsubstituted, but may also be substituted with non-influencing substituents.

Oxybenzoyl polyesters that can be used in the present invention

nelse can be used together with different fillers and in amounts which either promote or which, in a minimum amount, do not affect the desired properties. Examples of suitable fillers include glass fibres, painted glass, polytetrafluoroethylene, pigments and fillers as well as mixtures of these.

Although ovenware or fireproof dishes made from compositions that include oxybenzoyl polyesters and various fillers of the type mentioned above meet most of the requirements mentioned earlier, they do not have the smooth and satisfactory appearance that results in a commercially satisfactory product. In addition, it has been observed that many of the above-mentioned fillers create too strong bubble formations in baked goods at elevated temperatures.

One has in accordance with the present invention

found that said oven articles can have a uniform and satisfactory appearance without suppressing said unwanted bubbling or reducing it to a minimum, by adding talc to said oxybenzoyl compositions which contains a minimal amount of substances that decompose during

high temperature, e.g. up to 800°C, e.g. magnesium carbonate. Among the many types of talc available on the market, there are products that have a high purity, that are selectively produced from different ores or that have been calcined or subjected to acid treatment.

The talc types used in the present invention are characterized by low weight loss on combustion, a low iron content when analyzed for iron oxide and a precisely regulated particle size.

The weight loss when burning suitable talc should not be

more than 6% or less at 950°C and should be 2% or less at 800°C. The iron content analyzed as iron oxide (Fe20^)

must not be more than 1%, and particularly preferred types of talc, the iron content will not be more than approx. 0.6% or less.

Experiments and tests have shown that it is very important

that one uses such types of talc to achieve the purpose of the present invention. The use of other forms of talc does not give satisfactory properties to the finished product. However, such other forms of talc can be used together

with the talc specified above, and then in amounts from approx. 0.05 to approx. 20% in relation to the desired forms of talc.

Talc containing said minimal amount of decomposable

only compounds will be used in amounts of from 1 to 60%,

based on the total weight of the composition, and the preferred range is from 35 to approx. 55%.

Rutile titanium dioxide can also be used together with the talc material,

and includes mixtures of highly refined talc or other types of talc. The rutile titanium dioxide can be present in an amount from approx. 2 to approx. 20% based on the weight of the total composition. The preferred area is from approx.

5 to approx. 15%.

In casting compositions according to the present invention, the resin will usually make up from approx. 35 to approx. 85%, and the total amount of inert substances will vary from approx. 65 to approx.

15%. To achieve optimal results, the inert substances should amount from approx. 40 to approx. 55% of the casting compositions.

The inert substances will be able to make up to 55% of high-energy

nert talc and from approx. 0 to approx. 10% of titanium dioxide.

Although all of the aforementioned resins are suitable for use in the present invention, they are. preferred to use the resin where the dibasic acid, said hydroxy-aromatic acid and the aromatic diol are present in a molar ratio of approx. 1:2:1. You can also use other molar ratios, and resins have been used where the molar ratios between e.g. terephthalic acid, p-hydroxybenzoic acid and biphenol are 1:3:1, 1:5:1, 1:7:1 and 1:3.5:1. One can also

use physical mixtures of resins with different proportions of reactants.

Compositions according to the present invention can be produced by extrusion in accordance with commonly known techniques. E.g. a twin-screw extruder can be used with the addition of the polymer, the aforementioned talc and titanium dioxide at the supply opening and with the addition of the glass both at the outlet and inlet.

Compositions produced in the above-mentioned manner can then be injection-moulded using commonly known techniques.

The invention is further illustrated by means of the following examples where all parts and percentages are per weight unless otherwise stated. These non-limiting examples are only intended as illustrations and are thus not considered to be limiting of the invention in any way whatsoever.

EXAMPLE 1

This example illustrates the synthesis of a copolyester which

can be used in the present invention.

The following amounts of the following ingredients were mixed

as described below.

Articles A-D were added to a four-neck round-bottomed flask equipped with a thermometer, a stirrer, a combined inlet for HC1 and nitrogen and an outlet connected to a condenser. Nitrogen was introduced slowly through the inlet. The flask and its contents were heated to 180°C, after which HCl was bubbled through the reaction mixture. The outlet temperature was maintained at 110-120°C by external heating during the reaction with p-hydroxybenzoic acid and the phenol acetate ester.

The flask and its contents were stirred at 180°C for 6 hours, after which the HCl supply was switched off, the outlet temperature was raised to 180-190°C and the mixture stirred at 220°C for 3 hours. At this point, 159 g of distillate had collected in the cooler. Article F was then added, and the temperature gradually increased

from 220-320°C during 10 hours (10°C/hour). Stirring was continued at 320°C for 16 hours and then for a further 3

hours at 340°C, whereby a porridge or suspension was formed. The total quantity of distillate which consisted of phenol, acetic acid and phenylacetate then amounted to 384 g. Article G

was added and the reaction mixture cooled to 70°C. 750*

ml of acetone was added, the suspension was filtered and the solids were extracted in a Soxhlet apparatus with acetone to remove articles C and G. The solid was dried in vacuo at 110°C overnight, whereby the resulting copolyester (320 g, 89.2% of the theoretical yield) could be recovered as a granular powder.

EXAMPLE 2

518 parts of isophthalic acid, 1557 parts of terephthalic acid, 5175 parts of para-hydroxybenzoic acid, 6885 parts of acetic anhydride and 2325 parts of p,p'-bisphenol were mixed and refluxed for 17 hours at approx. 180°C,~after which the reflux condenser was replaced by a distillation column, and the temperature raised to 345°C within an hour and a quarter. The reaction mixture was stirred throughout the heating, and in particular there was vigorous stirring when the temperature was raised to 345°C. A yield of polymer of 8020 could be obtained

parts besides 8010 parts distillate. The contents of the reaction vessel were removed, cooled and ground to a particle size of between 20 and 160 mesh, US standard sieve series. resin

sen has a molecular weight of between 5,000 and 20,000, with an average weight roughly in the middle of the aforementioned variation range. The product was estimated to be approx. 50% crystalline.

The resin particles were held under a vacuum at an elevated temperature at an absolute pressure of 100 mm of mercury for 8

hours, and was then recovered as a granular powder.

EXAMPLE 3

The following quantities of the following ingredients were mixed

as indicated.

Articles A-D were heated to 145°C and refluxed overnight. The reflux cooler was removed, and a distillation column was inserted in its place. The mixture was heated with stirring at a rate of 20°C/hour to 300°C, after which the contents of the reactor were withdrawn. At this point, 92-94% of the theoretical amount of acetic acid had been collected. The prepolymer was ground and processed as in example 2, using a temperature from 250-375°C.

EXAMPLE 4 - _ _ -

Articles A-D were heated to 130°C and held at this temperature for one hour. The reaction is exothermic and precautions must be taken to keep the temperature at 130°C. The contents were then heated to 155°C for one hour and then at 180°C for 4 hours. The mixture was then cooled to 150°C and Article E was added, further reducing the temperature to 140°C. Article F was then added. The mixture was refluxed for 1 hour at 155°C, after which the reflux condenser was replaced with a distillation column. While distilling off the acetic acid formed, the contents of the reactor were kept at 330°C for 3 hours. The suspended polymer was cooled to 250°C and the mixture passed through a filter. The solid product was worked up with trichlorethylene to remove the heat transfer fluid.

The dried powder was processed in vacuo as described

in example 2.

EXAMPLES 5, 6 and 7

The method from example 3 was used, using the amounts of ingredients indicated.

EXAMPLE 8

268 parts of biphenol, 296 parts of para-hydroxybenzoic acid, 693.4 parts of acetic anhydride and 238 parts of terephthalic acid were mixed and heated to a temperature of 315°C during 5 hours with a temperature rise of 30°C/hour. The reaction mixture was stirred throughout the heating. When a temperature of 315°C was reached, the polymer content was removed from the reaction vessel and ground to a particle size of between 20 and 200 mesh, US standard sieve series. The resin particles were immediately placed in an oven at a temperature of 354°C and kept there for 16 hours, after which the product was recovered as a granular powder.

EXAMPLE 9

A casting composition was prepared from the polymer from Example 8 by extruding a mixture of 257.5 parts of the polymer from Example VIII, 30 parts of rutile titanium dioxide and 212.5 parts of high purity talc with the same structure as natural talc, and with a weight loss of 2 % by weight, an iron content analyzed as Fe^O^ of 0.5% and a particle size distribution where 95% of the particles were smaller than 40 µm.

The resulting mixture was injection molded into shaped balls or molds having a uniform and satisfactory appearance and showing no cracking or blistering at minimum temperatures of about 260°C.

Some of the shaped articles were subjected to a spot test where a blob of barbecue sauce was placed at the bottom of the container. This was then placed in a preheated oven at 177°C for 1 hour. At this point the sauce was thick, dark and crusty. The contents of the container were washed out with soap and water, using a sponge. The container was examined for stains and color difference and the differences

equal areas in the container were compared - but the differences_ were very, very small.

Certain other articles were subjected to a drop test where

five articles were toppled off a bench of continuously increasing height to determine their ability to withstand a drop-

blow without significant damage. The mean for these samples was one meter.

The results of all these samples indicate that they cast

articles according to the present invention are very well suited as containers or forms for the production of foodstuffs.

EXAMPLE 10

A molding composition was prepared from a polymer prepared

as described in example 8, by extruding a mix

ding of 271 parts of the polymer and 10 parts of talc of the same type as used in example 9.

The resulting mixture was injection molded at a screw speed of 100 rpm, an injection pressure of 143

kg/cm<2>and a temperature of 355°C in zone 1, 360°C in zone 2

and 345°C in zones 3 and 4.

Molded articles with a generally satisfactory appearance were produced.

EXAMPLES 11 - 18

In these examples, 257.5 parts of the resin product from examples 1-8 were mixed with 202.5 parts of the type of talc used in example 9, as well as 40 parts of rutile titanium dioxide by passing through a twin screw extruder. The reinforced resin compositions were then molded by injection molding. The molded articles had a satisfactory appearance and were resistant to cracking and blistering at elevated temperature.

Claims (43)

Bakeware article that can be used multiple times and that includes a molded aromatic polyester composition, characterized in that said composition includes from 35 to 65% of an aromatic polyester and from 1 to 60% of a talc containing a minimal amount of substances that decompose at elevated temperature. 2. Article according to claim 1, characterized in that said aromatic polyester is an oxybenzoyl polyester. 3. Article according to claim 2, characterized by also containing from approx. 2 to approx. 20% rutile titanium dioxide. 4. Article according to claim 3, characterized in that said talc has a weight loss on combustion of no more than 6% at 950°C and an iron content analyzed as iron oxide of no more than 1%. 5. Article according to claim 4, characterized in that the amount of talc in the composition is from approx. 35 to approx. 55%. / > 35 tolj fr) 6. Article according to claim ^, characterized in that the amount of rutile titanium dioxide varies from approx. 5 to approx. 15%. 7. Article according to claim 4, characterized in that said talc is selected from the group consisting of high-purity talc, highly refined talc, calcined talc and acid-treated talc. 8. Article according to claim 3, characterized in that said oxybenzoyl polyester contains repeating end units selected from the group with one or more of the following formulas: where x is 0, S, NH or SG^ and n is 0 or 1, and where the sum of the numbers p + q + r + s + t + uide groups present varies from approx. 3 to approx. 800. 9. Article according to claim 8, characterized in that the ratios q/r, q/u, t/t, t/u, q + t/r + u and t/t + u vary from approx. 10 to approx. 11/10. 10. Article according to claim 9, characterized in that the ratio is 10 to 10. 11. Article according to claim 2, characterized in that the oxybenzoyl polyester has repeating units with the formulas I, III and IV: where x is --0-- or SG^ -, m is 0 or 1, n is 0 or 1, q:r = 10:15 to 15:10, p:q = 1:100 to 100:1, p + q + r = 3 to 600, and the carbonyl groups of the groups of formula I or II are connected to the oxy groups of the group of formula I or III, and the oxy groups in the groups of formulas I or III are attached to the carbonyl groups in the groups of formula I or II. 12. Article according to claim 2, characterized in that the oxybenzoyl polyester has repeating units with the formula: 13. Article according to claim 7, characterized in that n is 0. 14. Article according to claim 10, characterized in that p + q + r = from 20 to 200. 15. Article according to claim 1, characterized in that said talc is highly refined talc. 16. Article according to claim 1, characterized in that said talc is calcined talc. 17. Article according to claim 1, characterized in that said talc is acid-treated talc. 18. Article according to claim 1, characterized in that said talc is pure talc. 19. Procedure for --Ær-eTttsirrlirtg. of food _in-_ _ containers that can be used several times, and where the food in said container is heated to serving temperature, characterized by placing the food in a molded article made from an aromatic polyester composition, and where said composition contains from approx. 35 to approx. 65% of an aromatic polyester, and from approx. 1 to approx. 60% of a talc containing a minimal amount of substances that decompose at elevated temperatures. 20. Method according to claim 19, characterized in that the aromatic polyester is an oxybenzoyl polyester. 21. Method according to claim 20, characterized in that the oxybenzoyl polyester composition contains from approx. 2 to approx. 20% rutile titanium dioxide. 22. Article JL according to claim 21, characterized in that said talc has "a weight loss on combustion of no more than about 6% at 950°C and an iron content, analyzed as iron oxide, of no more than about 1%." 23. Article according to claim 22, characterized in that the amount of talc in the composition varies from approx. 35 to approx. 55%. 24. Article according to claim 23, characterized in that the amount of rutile titanium dioxide varies from approx. 5 to approx. 15%. 25. Method according to claim 22, characterized in that said talc in the oxybenzoyl polyester composition is selected from the group consisting of highly refined talc, calcined talc and acid-treated talc. 17 26. Method according to claim 21, characterized in that the oxybenzoyl polyester contains repeating units selected from the group of one or more of the following formulas:- where x is 0, S, NH or SG^ and n is 0 or 1 and the total sum of the numbers p + q + r + s + t + uide groups present is from approx. 3 to approx. 800. 27. Method according to claim 26, characterized in that the ratios q/r, q/u, t/t, t/u, q + t/r, q + t/r -f u and t/t + u in the article according to claim 1 are from approx. 10 to approx. 11/10. 28. Method according to claim 27, characterized in that the ratio is 10 to 10. 29. Method according to claim 20, characterized in that the oxybenzoyl polyester has repeating units with the formulas I, II and III: where x is --0-- or SO^ -; m is 0 or 1; n is 0 or 1; q:r = 10:15 to 15:10, p:q = 1:100 to 100:1; p + q + r = from 3 to 600; and the carbonyl groups in the groups of formulas I or II are bonded to the oxy groups in the groups of formulas I or III, and the oxy groups in the groups of formulas I or III are bonded to the carbonyl groups in the groups of formulas I or II. 30. Method according to claim 22, characterized in that the heat source is thermal. 31. Method according to claim 22, characterized in that the heat source is a microwave. 32. Method according to claim 26, characterized in that the heat source is thermal. 33. Method according to claim 26, characterized in that the heat source is a microwave. 34. Polyester molding composition, characterized by containing from approx. 35 to approx. 65% aromatic polyester, from approx. 1 to approx. 60% of a talc containing a minimal amount of substances that decompose at elevated temperatures. 35. Molding composition according to claim 34, characterized in that the aromatic polyester is an oxybenzoyl polyester. 36. Composition according to claim 34, characterized by containing from approx. 2 to approx. 20% rutile titanium dioxide. 37. Article according to claim 36, characterized in that said talc has a weight loss on combustion of no more than approx. 6% at 950°C, and an iron content, analyzed as iron oxide, of no more than approx. 1%. 38. Article according to claim 37, characterized in that the amount of talc in the composition is from approx. 35 to approx. 55%. 39. Article according to claim 38, characterized in that the amount of rutile titanium dioxide is from approx. 5 to approx. 15%. 40. Composition according to claim 37, characterized in that said talc is selected from the group consisting of high purity talc, highly refined talc, calcined talc and acid treated talc. 41. Polyester molding composition according to claim 37, characterized in that the polyester contains repeating units selected from the group with one or more of the following formulas: where x is 0, S, NH or SG^ and n is 0 or 1, and the total sum of the numbers p+q+r+s+t+uide groups present is from approx. 3 to approx. 800. 42. Polyester molding composition according to claim 37, characterized in that the oxybenzoyl polyester contains repeating units with the formulas I, III and IV: where x is -0- or SO^ -; m is 0 or 1; n is 0 or 1, q:r = 10:15 or 15:10, p:q = 1:100 to 100:1, p + q + r = from 3 to 600, and the carbonyl groups of the groups of formulas I or II are bonded to the oxy groups of the groups of formulas I or III; and the oxy groups in the groups of formulas I or III are attached to the carbonyl groups in the groups of formulas I or II. 43. Polyester molding composition according to claim 37, characterized in that the oxybenzoyl polyester contains repeating units with the formula: