LU84809A1 - ASSEMBLY COMPOSITIONS, COOKING UTENSILS MANUFACTURED THEREOF, AND USE OF SUCH UTENSILS - Google Patents

Description

"Assembly compositions, cooking utensils made from these compositions and use of these utensils" _

The present invention relates to molding compositions, to cooking utensils made from these compositions and to the use of these utensils.

It is known that certain plastics have found certain applications in the field of cooking utensils. For example, polymethylpentene has been used for injection molded trays which can be used for the preparation of food products. Polysulfone has also been used in applications for the preparation of food products. However, no satisfactory material has been found which can be used in the wide ranges of conditions and requirements which are encountered in the provision of cooking vessels or utensils, which can be used either in thermal ovens either in microwave ovens.

In addition to the obvious fact that the material must be able to withstand the temperatures encountered in the heat source used for cooking, the material must exhibit a particular combination of a number of other characteristics before the cookware made from the material can be successfully used in food preparation. The material must have good electrical properties. It must be able to undergo significant thermal shock by the fact that the cooking utensil prepared therefrom must be capable of passing from conditions of extreme cold to high temperatures over relatively short periods of time. The material must have good hardness and impact resistance and have a high tensile and flexural strength. It must also be able to resist boiling water, food acids and grease and the harmful effects of immersion in detergents.

With regard to properties related to food, the material must be able to confer on the cooking utensil made from it resistance to soiling by a wide range of food materials. It must have a surface offering good anti-stick properties, an ability to be easily removed for the food it contains. It must not emit or release any volatile matter and it must not contain any extractable component. And in addition to meeting all of the foregoing requirements, articles made from this material should provide a pleasant and generally uniform appearance so that they can be marketed.

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According to the present invention, kitchen utensils which meet the strict requirements of the cooking container market are obtained by manufacturing the cooking utensils from a plastic material based on fully aromatic polyesters, and more particularly oxybenzoyl polyesters.

The fully aromatic polyesters used in accordance with the present invention are made up of combinations of repeating moieties selected from the group consisting of one or more of the following formulas: i5 I p - * oc 20 hq 25 "» -CO "" "'ni r iv 4 -_oc ^ GC ^ co ““ “° · £ 0 · ° 7 V * VI u 5 in which χ represents 0, S, - -, NH or SC> 2, n is equal to 0 or 1 and and the total of the integers p + q + r + s + t + u in the fragments present is from about 3 to about 800.

The combinations of the aforementioned fragments include the linking of the carbonyl group of formulas I, II, IV and V with the oxy group of formulas I, III, IV and VI. In the most general combination, all of the fragments corresponding to the above-mentioned formulas may be present in a single copolymer. The simplest embodiment would consist of homopolymers of fragments I or IV. Other combinations consist of mixtures of fragments II and III, II and VI, III and 20 V, V and VI, and I and IV.

The location of the functional groups is preferably in the para (1,4) position. They can also be arranged in ortho position (1,2) with respect to each other. With regard to the naphthalene fragment, the most interesting locations of the functional groups are in positions 1.4, 1.5 and 2.6. These groups can also be in ortho position with respect to each other.

The symbols p, q, r, s, t and u are whole numbers and indicate the number of fragments present in the polymer. The total sum of 5 (p + q + r + s + t + u) can vary from 3 to 800 and, when present, the ratios q / r, q / u, t / r, t / u, q + t / r, q + t / r + u and t / r + u can vary from approximately 10/11 to approximately 11/10, the 5 most interesting ratio being 10/10.

Examples of materials from which the fragments of formula I can be obtained are ρ-hydroxybenzoxque acid and its esters, such as phenyl p-hydroxybenzoate, p-acetoxÿbenzoxque acid and p-acetoxybenzoate. isobu-tyle. Materials from which the fragment of formula II can be obtained are terephthalic acid, isophthalic acid, diphenyl terephthalate, diethyl isophthalate, methyl-ethyl terephthalate and isobutyl hemi-ester terephthalic acid. Among the compounds making it possible to obtain the fragment of formula III, mention will be made of p, p'-bipbenol, 4,4'-dihydroxy-benzophenone, resorcinol and hydroquinone. It will be found that these materials are also suitable to obtain the fragments of formulas VI-VIII.

Examples of monomers corresponding to formula IV are 2-hydroxy-6-naphthoxic acid, 6-hydroxy-1-naphthoxque acid, 5-acetoxy-1-naphthoic acid and 5-hydroxy-1 -phenyl naphthoate. Monomers corresponding to formula V are 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid and 2,6-naphthalene-dicarboxylic acid. The diphenyl esters or dicarbonyl chlorides of these acids can also be used. Examples of particular monomers corresponding to formula VI are 1,4-dihydroxynaphthalene, 2,6-diacetoxynaphthalene and 1,5-dihydroxy-naphthalene.

Particularly advantageous in the context of the present invention are plastics based on oxybenzoyl polyesters.

A preferred class of oxybenzoyl polyesters are the copolymers of re-petitive fragments of formulas VIII and IX: (VIII> Γ o / ¾. ° Ί f 15 q (IX).

——0 ~ ("· —0 ^ -.

20 I— n -1 r

in which x represents -O or -SO2 “/ ni is equal to 0 or 1, n is equal to 0 or 1, q / r = 10/15 to 15/10, p / q = 1/100 to lOO / l , and p + q + r = 3 to 600 and preferably 20 to 200. The carbonyl groups of the fragment of formula I or III are linked to the oxy groups of a fragment of formula I or IV; the oxy groups of the fragment of formula I or IV are linked to the carbonyl groups of the fragment of formula I or III

Another group of aromatic polyesters which can be used are aromatic polyesters containing repeating fragments of the 2,6-dicarboxynaphthalene fragment and / or the p-oxybenzoyl fragment and the symmetrical dioxy aryl fragment, as well as variants of these. These polyesters are described in US Patents 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, 4.265.802, 10 4.279.603, 4.318.841 and 4.318.842.

The preferred copolyesters contain repetitive fragments of the formula X: (X) 15 o r - - o "" 't o 0 / 3- °: - 25

The synthesis of these polyesters is described in detail in US Patent No. 3,637,595, entitled "P-Oxybenzoyl Copolyesters", incorporated in the context of the present invention by way of reference.

The polyesters used in the context of the present invention can also be chemically modified by various means, such as by incorporating into the polyester monofunctional reagents, such as benzoic acid, or trifunctional reactants or having a higher functionality, such as trimesic acid. The benzynic rings in these polyesters are preferably unsubstituted but may be substituted by non-interfering substituents.

The oxybenzoyl polyesters of interest within the scope of the present invention can be used with different types of fillers and in amounts which promote or at least do not materially alter the desired properties. Examples of interesting fillers are, among others, glass fibers, crushed glass, polytetrafluoroethylene, pigments, fillers and combinations of these different elements.

Although the cooking utensils prepared from compositions comprising the oxybenzoyl polyesters and the various fillers mentioned above meet the general requirements referred to above, they do not have the pleasant, uniform appearance necessary for a product which can be commercially available. In addition, it has been observed that a large number of fillers produce an excess of bubbles in the cookware at high temperatures.

It has been found, according to the present invention, that it is possible to impart a uniform and pleasant appearance to articles or cooking utensils and to suppress or minimize the formation of undesirable bubbles by the introduction into the oxybenzoyliques compositions. from which these utensils or articles are molded, talc which contains a minimum amount of materials decomposable at elevated temperatures, for example up to about 800 ° C, such as magnesium carbonate. Among the talcs of this type, mention will be made of high purity talcs, 10 talcs selectively combined from various ores or talcs which have been calcined or subjected to an acid treatment.

The talcs which are used in the context of the present invention are characterized by a low loss of roasting weight, a low iron content analyzed in the form of iron oxide and a closely controlled particle size.

The weight loss on toasting of suitable talcs is not more than about 6% or less at 950 ° C and is 2% or less at 800 ° C. The iron content, analyzed for iron oxide (Fe 2 O 3), will not be more than about 1% and that of the particularly preferred talcs will not be more than about 0.6% and may be less than this value.

Experiments and tests carried out have demonstrated quite clearly that it is essential to use a talc of this type to achieve the aims of the present invention.

The use of other forms of talc does not give satisfactory properties to the molded product 10 or 11. However, these other forms of talc can be used in conjunction with the specified talc in amounts ranging from about 0.05% to about 20% of the required forms of talc.

The talcs containing the minimum amount of decomposable material will be present in amounts ranging from about 1% to about 60% based on the weight of the total composition, the preferred range being from about 35% to about 55%.

Rutile titanium dioxide can also be used in conjunction with the talc-forming material, including mixtures of highly refined talcs and other talcs. Rutile titanium dioxide will be present in an amount of from about 2% to about 20% based on the weight of the total composition. The preferred range is from about 5% to about 15%.

In the molding compositions of the present invention, the resin will constitute one way. general about 35% to about 85% of the composition and total inert materials about 65% to about 15%. For optimum results, the inert materials will constitute about 40% to about 55% of the molding compositions. The inert materials will comprise up to about 55% highly refined talc and about 0 to about 10% titanium dioxide.

Although all of the above-mentioned resins are useful in the context of the present invention, it is preferable to use a resin * 11 in which the dibasic acid, hydroxy-aromatic acid and the aromatic diol are present in molar proportions about 1/2/1. Other molar proportions may be used and resins have been used in which the molar proportions of terephthalic acid, p-hydroxybenzoic acid and biphenol are, for example, 1/3/1, 1 / 5/1, 1/1/1, and 1 / 3.5 / 1. Physical mixtures of resins in which different proportions of reactants have been used are also found to be suitable.

The compositions of the present invention can be prepared by extrusion according to generally known practice. For example, a twin screw extruder can be used by adding the polymer, selected talc and titanium dioxide to the feed neck and adding glass roving to both the aeration and feed necks.

The compositions thus obtained can then be injection molded according to general practice using techniques known in the field of injection molding.

The invention is further illustrated by the following Examples, in which all parts and percentages are by weight, unless otherwise indicated. These examples illustrate certain forms of realization carried out according to the invention but in no way constitute a limitation thereto.

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Example 1

This example illustrates the synthesis of a copolyester which can be used in the context of the present invention.

The following quantities of the ingredients given below are combined as indicated.

Denomination - Nation quantity Ingredient gr '- Moles A P-hydroxybenzoic acid 138 1 10 B Phenyl acetate 170 1.25 C' Thérminol 77 500 D Diphenyl terephthalate 318 1 E Hydrochloric acid - - P Hydroquinone 111 1.01 15 G Thérminol 77 500

Ingredients A-D are loaded into a four-necked flask equipped with a combined thermometer, stirrer, nitrogen inlet and HCl outlet connected to the refrigerant. Nitrogen 20 is brought slowly through the inlet. The container and its contents are heated to 180 ° C, which results in the bubbling of HCl in the reaction mixture. The outlet head temperature is maintained at 110 ° -120 ° C. by external heating during the exchange reaction ‘between p-hydroxybenzoic acid and the ester constituted by phenyl acetate.

The container and its contents are stirred at 180 ° C for 6 hours, period after which the release of HCl is stopped, the outlet head temperature is raised to 180 ° C-190 ° C

13 and the mixture is stirred at 220 ° C for 3.5 hours. Up to this point, 159 g of distillate are collected in the condenser. The ingredient P is then added and the temperature is gradually raised from 220 ° C to 320 ° C over a period of 10 hours (10 ° C / hour). Stirring is continued at 320 ° C for 16 hours and then for an additional 3 hours at 340 ° C so as to obtain a pSte. The total amount of distillate, formed from phenol, acetic acid and phenyl acetate, was 384 g. Ingredient G is added and the reaction mixture is allowed to cool to 70 ° C. Acetone (750 ml) is added and the paste is filtered, the solids being ex-treated in a Soxhlet with acetone to separate the ingredients C and G. The solids are dried under vacuum at 110 ° C overnight, which allows the resulting copolyester to be recovered (320 g; 89.2% of theoretical yield) in the form of a granular powder.

Example 2 518 parts of isophthalic acid, 1557 parts of terephthalic acid, 5175 parts of para-hydroxÿbenzoic acid, 6885 parts of acetic anhydride and 2325 parts of p, p'-bis-phenol are mixed together and heated at reflux for 17 hours at a temperature of about 180 ° C, after which the reflux condenser is replaced by a distillation head and the temperature is raised to 345 ° C over a period of 1 1/4 hours. The reaction mixture is stirred throughout the heating period, this reaction mixture being particularly intimately mixed during the period during which the temperature is raised to 345 ° C. The polymer production is 8020 parts and 5 8010 parts of distillate are recovered. The contents of the reaction vessel are removed, cooled and ground to particle sizes in the range of 0.83 mm to 0.095 mm. The resin obtained has a molecular weight in the range of 5,000 to 20,000, an average weight approximately corresponding to a value in the middle of this range. It is evaluated that the product is approximately 50% crystalline.

The resin particles are, for example, kept under vacuum at an elevated temperature and at an absolute pressure of about 100 mm of mercury for 8 hours and recovered in the form of a granular powder.

Example 3

The following amounts of the following ingredients are combined as indicated.

Denomination - Nation quantity Ingredient gr Moles A Terephthalic acid 291 1.75 B P-hydroxybenzoic acid 483 3.50 25 C p, p1-biphenol 325 1.75 D Acetic anhydride 755 7.40

The ingredients A-D are heated to 145 ° C and heated at reflux overnight.

The reflux condenser is removed and replaced with a distillation head. The mixture is heated with stirring at 20 ° C / hour to 300 ° C and the contents of the reactor are removed.

At this time, about 92-94% of the theoretical acetic acid is collected. The prepolymer is ground and treated as in Example 2, using a temperature of about 250 ° -375 ° C.

Example 4 Denomination Nation quantity Ingredient gr Moles A P-hydroxybenzoic acid 276.0 (2.00) 10 B Terephthaloyl chloride 203 1.0 C Trimesic acid 8.4 0.040 D Therminol 66 1274 E p, p'-biphenol 186 1.0 F acetic anhydride 224.6 2.2 15 The ingredients AD are heated to

130 ° C and kept there for 1 hour. The reaction is exothermic and care must be taken to maintain the temperature at 130 ° C. The contents are heated to 155 ° C for 1 hour and 180 ° C for 4 hours. The mixture is then cooled to 150 ° C.

and the ingredient E is added, the temperature then being lowered again to 140 ° C. Ingredient F is then added. This mixture is refluxed for 1 hour at 155 ° C and the reflux condenser is replaced by a distillation column. While distilling the acetic acid formed, the contents of the reactor are heated to 330 ° C and kept there for 3 hours. The polymer in suspension is cooled to 250 ° C. and the mixture is filtered. The solid material is treated with trichlorethylene to separate the heat transfer fluid 16. The dried powder is then treated under vacuum as in Example 2.

Examples 5, 6 and 7

The process of Example 3 is repeated using the following amounts of the indicated ingredients.

Denomi- Quantity in moles nation Ingredient Ex. 5 'Ex. 6 Ex. 7 A Terephthalic acid 1 1.1 10 B P-hydroxÿbenzoic acid 345 C p, p'-biphenol 1 1 1 D Acetic anhydride

Example 8 268 parts of biphenol, 396 parts of para-hydroxybenzoic acid, 693.40 parts of acetic anhydride and 238 parts of terephthalic acid are mixed and heated to a temperature of 315 ° C over a period of 5 hours at a temperature rise rate of 30 ° C per 20 hours. The reaction mixture is stirred throughout the heating period. When the temperature of 315 ° C is reached, the polymer content is separated from the reaction vessel and ground to a particle size of 0.83 mm to 0.074 mm. The resin particles are introduced into an oven and gradually brought to a temperature of 354 ° C. over a period of 16 hours and recovered in the form of a granular powder.

Example 9 A molding composition is prepared from the polymer of Example 8 by extruding a mixture of 257.5 parts of the polymer of Example 17 8, 30 parts of rutile titanium dioxide and 212.5 parts of a high purity talc having the platelet structure of natural talc, a loss on roasting of 2% by weight, an iron content *. 5 analyzed for Fe2 ° 3 ^ e 0/5% and a particle size distribution in which more than 95% of the particles are less than 40 microns.

The resulting mixture is injection molded so as to obtain molded bowls of a pleasant, uniform appearance which do not show any cracking or blowing at minimum temperatures of about 260 ° C.

Some of the molded articles are subjected to a stain test in which a spoonful of rotisserie sauce is deposited on the bottom of the molded container. The container is then placed in an oven preheated to 177 ° C for 1 hour. At this time, the sauce is thick, dark and has a crust structure. After cooling, the container is washed with soap and water using a Scrunge pad.

The container is examined for stains and the difference in color is noted between the stains or stains and the non-stained areas. The difference observed is very slight.

Certain other samples are subjected to a drop test in which five samples are dropped on their upper outer perimeter from gradually increasing heights to determine their ability to withstand the impact of the drop without significant damage.

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The average for these samples is 101.6 cm.

The results of these tests all show the suitability of the molded articles for use as a cooking container for food.

5 Example 10

A molding composition is prepared from a polymer obtained according to Example 8, by extruding a mixture of 271 parts of polymer and 10 parts of the talc used in Example 10 9.

The resulting mixture is injection molded at a screw speed of 100 revolutions per minute, at an injection pressure of 13.6 MPa and at temperature settings of 355 ° C in zone 1, of 360 ° C in zone 2 and 345 ° C in zones 3 and 4.

Molded articles are obtained which have a generally pleasant appearance.

Examples 11 to 18 In these examples, 257.5 parts of the resinous products of Examples 1 to 8 are mixed with 202.5 parts of the talc used in Example 9, with 40 parts of rutile titanium dioxide by passing them through a twin-25 screw extruder. The reinforced resinous compositions obtained are shaped by injection molding.

The molded articles obtained have a satisfactory appearance and a satisfactory resistance to cracking and blowing at high temperatures.

. I> v

Claims (13)

1. A polyester-based molding composition, characterized in that it comprises about 35 to about 55% of aromatic polyester, and about 1 to about 50% of a talc having a te--. minimum of decomposable materials at high temperature. 1§ 2. A molding composition according to claim 1, characterized in that the aromatic polyester is an oxybenzoyl polyester. 3. Composition according to either of Claims 1 and 2, characterized in that it contains approximately 2 to approximately 20% of rutile titanium dioxide, in particular approximately 5 to approximately 15%. 4. Composition according to any one of claims 1 to 3, characterized in that the talc is of a type having a loss in weight on roasting, which is not greater than about 5% at 950 ° C , and an iron content, analyzed for iron oxide, which is not more than about 1%. 5. Composition according to any one of claims 1 to 4, characterized in that the amount of talc of this composition is from about 35 to about 55%. 6. Composition according to any one of claims 1 to 5, characterized in that the talc is chosen from the group comprising talcs of high purity, highly refined talcs, calcined talcs and acid-treated talcs. 50 7. A polyester-based molding composition according to any one of claims 1 to 6, characterized in that the polyester comprises repetitive fragments chosen from group r 5 comprising one or more of the following formulas: f0 (O "ix, ) rO “ä“ ï p, I _____ I. - - 10 l— n —q I II 15 - ~ ir i ~ ni 20 '0 CO L s 25 IV t l_ - u V; VI 21 in which x represents 0, S, - 9 -, NH or * "C SC> 2 and n is equal to 0 or 1, and the total of whole numbers p + q + r + s + t + u in the fragments present is from about 3 to about 800. 8. Molding composition according to either of Claims 7 and 8, characterized in that the ratios q / r, q / u, t / t, t / u, q + t / r, q + t / r + u and t / t + u are approximately 10/10 to approximately 11/10, in particular 10/10. 9. Molding composition based on poly ester according to claim 2, characterized in that the polyester oxybenzc yLique comprises repetitive fragments of each of the formulas I, II and III: P 20 Γ "0 /, - λ 0“ __iJ yë - - —q - r in which x represents —O or SO2 ”; m is equal to 0 or 1; n is equal to 0 or 1; q / r = 10/15 to 30 15/10; p / q = 1 / 100 to 100 / l; p + g + r = -3 to 600, in particular 20 to 200, the carbonyl groups of fragment 22 of formula I or II are linked to the oxy groups of the fragment of formula I or III, and the oxy groups of the fragment of formula I or III are linked to the carbonyl groups of the fragment of formula I or 5 il. ”- 10. Polyester-based molding composition according to claim 9, characterized in that the oxybenzoyl polyester comprises repetitive fragments of the formula: 10 Γ 0 -. 0 î “ 15 W / \ = J ^ === ^ J 11. A cooking utensil which can be used repeatedly, characterized in that it consists of a molded polyester composition according to any one of claims 1 20 to 10. 12. Method for preparing food in a cooking container of the permanent type, which can be used repeatedly, in which the food in the container is heated to a temperature allowing it to be served, characterized in that it consists in placing the food in a molded utensil according to claim 11. 13. A process for preparing food according to claim 12, characterized in that the heat source is a thermal or microwave source.