AT253784B - Process for the production of thermally stable formaldehyde high polymers - Google Patents

Description

  

   <Desc / Clms Page number 1>
 



  Process for the production of thermally stable formaldehyde high polymers
The invention relates to a process for the production of thermally stable formaldehyde high polymers, and in particular polyoxymethylene diets, from aqueous formaldehyde solutions.



   From our own Italian patent specification No. 646437 and our own Belgian patent specification No. 643195 it is known that the polymerization of formaldehyde from aqueous solutions at low temperature (<600C) is strongly catalyzed by soluble salts of organic or inorganic acids with alkali and alkali Alkaline earth metals at an alkaline pH value (> 7).



   It has now surprisingly been found that the polymerization of formaldehyde from aqueous solutions also by strong acids, both organic and inorganic with a pKa <2 for each
 EMI1.1
 conditions, both in terms of polymer formation per hour and the average molecular weight of the polymer, the conditions remaining constant for an unlimited period of time.



   Table I shows the catalytic effect of various acids compared with an experiment carried out in the absence of acids and at a pH of 10.4 0.2, the other working conditions remaining the same.



   From the table it can be seen that the use of acids enables higher average molecular weights (expressed as the reduced viscosity of the acetyl derivatives as described below) to be achieved.



   Table I.
Specific influence of some strong acids on the average molecular weight of the polymer under stationary conditions. T = 35oC: kinetics = 1.4 (the term "kinetics" means the total polymerization rate, expressed as the amount of aldehyde removed from the liquid phase in g per hour per 100 g of solid polymer introduced).

 <Desc / Clms Page number 2>

 
 EMI2.1
 
<tb>
<tb>



  Acid <SEP> Acid concentration <SEP> 11 <SEP> red <SEP> of the <SEP> erin <SEP>% by weight <SEP> of the <SEP> solution <SEP> containing <SEP> polymer
<tb> absent-0, <SEP> 28-0, <SEP> 30 <SEP>
<tb> (pH <SEP> 10, <SEP> 4 <SEP> ¯ <SEP> 0.2)
<tb> HSC <SEP> 10, <SEP> 68 <SEP> 0, <SEP> 65
<tb> HCIC <SEP> 9.24 <SEP> 0, <SEP> 56 <SEP>
<tb> HCI <SEP> 6, <SEP> 00 <SEP> 0, <SEP> 59 <SEP>
<tb> p-CH3C6H4SO3H <SEP> 15, <SEP> 69 <SEP> 0, <SEP> 52 <SEP>
<tb>
 
It was also found, surprisingly, that the catalytic effect of the acids increases by increasing their concentration in the liquid reaction phase up to a maximum value above which any further increase in the acid concentration causes a reduction in their catalytic effect.



   This fact is evident from the higher or lower average molecular weight of the polymer obtained under stationary conditions.



   There is therefore an optimal concentration range, which varies depending on the acid used, above and below which the catalytic activity decreases, for example from Tables II, m and IV, relating to the use of sulfuric, perchloric and hydrochloric acid, respectively can be seen.



   Table II
Influence of the sulfuric acid concentration on the average molecular weight of the polymer obtained under stationary conditions.



    T = 350C; Kinetics = 1, 4
 EMI2.2
 
<tb>
<tb> H2SO4 <SEP> concentration <SEP> in <SEP> #red <SEP> of the <SEP> received
<tb> of the <SEP> liquid <SEP> phase <SEP> in <SEP> wt. <SEP> -% <SEP> polymer
<tb> 1, <SEP> 94 <SEP> <<SEP> 0, <SEP> 1 <SEP>
<tb> 4, <SEP> 59 <SEP> 0.15
<tb> 6, <SEP> 50 <SEP> 0, <SEP> 28 <SEP>
<tb> 8. <SEP> 58 <SEP> 0.62
<tb> 10, <SEP> 68 <SEP> 0, <SEP> 65 <SEP>
<tb> 12, <SEP> 90 <SEP> 0, <SEP> 69 <SEP>
<tb> r <SEP> 16, <SEP> 10 <SEP> 0, <SEP> 60
<tb> 18. <SEP> 23 <SEP> 0, <SEP> 58
<tb> 21, <SEP> 30 <SEP> 0, <SEP> 51
<tb> 29, <SEP> 60 <SEP> 0, <SEP> 24 <SEP>
<tb> 42, <SEP> 30 <SEP> <<SEP> 0, <SEP> 1 <SEP>
<tb>
 
Table III
Influence of the perchloric acid concentration on the average molecular weight of the polymer obtained under stationary conditions.



   T = 35 C; Kinetics = 1, 4

 <Desc / Clms Page number 3>

 
 EMI3.1
 
<tb>
<tb> HClO4 <SEP> concentration <SEP> received in <SEP> #red <SEP> of the <SEP>
<tb> of the <SEP> liquid <SEP> phase <SEP> in <SEP> wt .-% <SEP> polymer
<tb> 6.49 <SEP> 0.37
<tb> 9.24 <SEP> 0.56
<tb> 12.12 <SEP> 0.57
<tb> 17.02 <SEP> 0.50
<tb> 22.04 <SEP> 0.35
<tb>
 
Table IV
Influence of the hydrochloric acid concentration on the average molecular weight of the obtained polymer under stationary conditions.
 EMI3.2
 
<tb>
<tb>



  HC1 <SEP> concentration <SEP> in <SEP> 1 / red <SEP> of the <SEP> received
<tb> of the <SEP> liquid <SEP> phase <SEP> in <SEP> by weight <SEP> polymer <SEP>
<tb> 2, <SEP> 27 <SEP> 0, <SEP> 27 <SEP>
<tb> 6. <SEP> 0, <SEP> 59 <SEP>
<tb> 8 <SEP> 0, <SEP> 56 <SEP>
<tb> 13.2 <SEP> 0.16
<tb>
 
 EMI3.3
 

 <Desc / Clms Page number 4>

 
 EMI4.1
 The acid liquid sets tration dietary ether in phase in wt .-% methanol in the under liquid stationary BePhase in conditions erGew .-% held polymer
 EMI4.2
 
SO4 10, present in commercially available aqueous formaldehyde solutions and formed by methanol
Dismutation of the aldehyde.



   Surprisingly, it was also found that when a neutral salt of an inorganic base with one of the aforementioned acids is added to the acid / alcohol system, a further increase in the percentage of polyoxymethylene dieters present in the polymer is achieved, as can be seen from Table VI, in which the features and Results of two experiments (one carried out in the presence of HCl and CHOH and the other in the presence of HCl, CHsOH and NaCl) are shown.



   Table VI
Proportion of polyoxymethylene dieters that are present in polymers obtained with HCl / CH5OH systems, with and without the addition of NaCl
 EMI4.3
 
<tb>
<tb> HCl <SEP> concentration <SEP> CH3OH <SEP> concentra- <SEP> NaCl <SEP> concentra- <SEP>% fraction <SEP> of the <SEP> polyine <SEP> of the <SEP> liquid <SEP > tion <SEP> in <SEP> the <SEP> tion <SEP> in <SEP> the <SEP> oxymethylene diether
<tb> phase <SEP> in <SEP> wt .-% <SEP> liquid <SEP> phase <SEP> liquid <SEP> phase <SEP> in <SEP> the <SEP> under <SEP> statioin <SEP> % By weight <SEP> in <SEP>% by weight <SEP> under <SEP> conditions
<tb> obtained <SEP> polymer
<tb> 4 <SEP> 5 <SEP> 0 <SEP> 25-35
<tb> 5, <SEP> 4 <SEP> 5, <SEP> 4 <SEP> 8,

   <SEP> 3 <SEP> 55-75 <SEP>
<tb>
 
The inventive method consists of suspending solid polyoxymethylenes obtained in any manner in aqueous formaldehyde solutions which have a CHO concentration between the equilibrium concentration and the stability limit of the system, at temperatures between 0 and 60 ° C., preferably between 20 and 400 ° C. in the presence of one or several organic or inorganic strong acids, with a pKa <2 for each hydrogen atom, their concentration in the solution between 0.5 and 31 gel.

   ils of the solution, and in the presence of an aliphatic alcohol (which is either present in the formaldehyde solution or is added from the outside), the concentration of which in the solution is less than 25% by weight, and a salt of an inorganic (which reacts neutrally in water) Base with one of the acids mentioned above, with a pKa <2 for each hydrogen atom whose concentration in the solution is less than or equal to the saturation concentration in the system.



   The components initially present in the solution are added either batchwise or continuously to the suspension thus obtained, in order to replenish those components used up during the process and to keep the composition of the liquid phase and the liquid / solid ratio constant over time.

 <Desc / Clms Page number 5>

 



   A process of this type can be carried out either in a single reactor or in different reactors, for example by working in cascade. For each reactor or for each reaction zone of the same reactor, the appropriate concentration of the reaction medium and feeds must be determined.



   The alcohols and salts used according to the invention must have at least a limited solubility in the reaction medium.



   All the polymers obtained by the process according to the invention have a crystallinity of 1000/0 (measured by X-ray) and have an essentially ortho-rhombic crystalline form.



   Although the invention is not intended to clarify the mechanisms of the reactions in the process according to the invention, but merely to be a description of the practical implementation of a process suitable for the production of useful substances, it is assumed that the following phenomena occur under the conditions described: Crystallization of the polyoxymethylene glycols and polyoxymethylene monoethers and polyoxymethylene dieters. of which the solution is oversaturated.



   - Increase in the molecular weight of the polyoxymethylene glycols and polyoxymethylene monoethers crystallized from the solution and of the polyoxymethylene glycols initially present in the solid phase due to topochemical reaction with the formaldehyde present in the solution.



   - Etherification of the terminal hydroxyls of the polyoxymethylene chains by reaction with the aliphatic alcohol present in the solution.



   Under the working conditions according to the invention, the three aforementioned reactions have such relative speeds that the solids reach a steady composition over time, as far as the ratios between the amounts of polyoxymethylene glycols, polyoxymethylene monoethers and polyoxymethylene diets are concerned, as well as with regard to the average molecular weight and the crystalline ones Structure.



     This makes it possible to operate according to a process in which the polymerization reaction and the blocking reaction of the terminal hydroxyls of the chains take place simultaneously to obtain high molecular weight polyoxymethylenes.



   The invention differs completely from that previously known in the literature. It is
 EMI5.1
 ger [190'7]. s. 10-11 and 20-26).



   However, it is also known (JF Walker "Formaldehyde" ACS Monograph No. 159 [1964], pp. 158 to 163) that C1- and 8-polyoxymethylenes are polymers with a low degree of polymerization (100-300) and therefore have no commercial value , whereas the polymers obtained by the process according to the invention have a high average degree of polymerization (> 500) and can be used with advantage as thermoplastic materials.



   It must be added that IX. and 8-polyoxymethylenes have the same crystalline structure as paraformaldehyde, namely the well-known hexagonal crystal structure which is entirely different from the ortho-rhombic crystal structure of the polymers obtained by the present process.
 EMI5.2
 painful amounts (less than 0, silo) non-volatile acids (Walker) and for the removal of formaldehyde-rich vapors with non-dissolving liquids (excluding water) in the presence of rLSO leads to the production of low molecular weight polymers (paraformaldehyde) in hexagonal crystalline form .



   The only process known in the literature which leads to the preparation of polyoxymethylenes with a high degree of polymerization (> 500) from aqueous or alcoholic formaldehyde solutions in an acidic medium is that described by N. Brown (US Pat. Nos. 3, 000, 860 and No. 3,000, 861), which is high molecular weight polyoxymethylene from aqueous or alcoholic form-

 <Desc / Clms Page number 6>

 aldehyde solutions by means of a two-step process in the presence of acids with a pKa> 2 for each hydrogen atom at temperatures above 600C at atmospheric pressure.

   The working conditions according to the invention are therefore completely different from those of Brown and the reaction system according to the invention therefore also shows a completely different behavior compared to those of Brown: This is shown by the fact that when the method according to the invention at the temperatures used by Brown (> 600C) or in the presence of the acids used by Brown (pKa> 2), the catalyst shows no effect and polyoxymethylenes with a very low degree of polymerization (<300) are obtained.



   Prior to the invention, only the production of polyoxymethylene diets with a very low molecular weight and no technical value from aqueous formaldehyde solutions was known (JF Walker "Formaldehyde" ACS Monograph No. 159 [1964], pp. 164-173), whereas high molecular weight polyoxymethylenes only essentially consist of anhydrous media and with large amounts of etherifying agents were obtained (Italian patents No. 682325 and No. 624568).



   All previously known polyoxymethylene dieters had a crystalline structure that belonged to the hexagonal system.



   In order to better illustrate the invention, some examples are given which, however, are not to be understood as a restriction thereto. During the experiments described in the examples, samples were taken at periodic intervals in order to determine the crystalline structure, the molecular weight of the solid and the proportion of polyoxymethylene dieters in the solid. Finally, the thermal stability of the doubly etherified product was then determined.



   For these determinations, each sample was washed with distilled water until the washing water reacted neutral and then with an amount of benzene corresponding to the weight of the samples.



   The product was then dried under 15 mm Hg for 12 hours at 430C.



   The crystalline structure was determined by X-ray using a method cited in the literature (G. Carazzolo and G. Putti. Chimica e Industria, 45, [1963] pp. 771-776).



   The determination of the molecular weight of the polymer obtained by polymerization was carried out by measuring the reduced viscosity at 1500 ° C. in dimethylformamide at a concentration of 0.51 °. For this purpose, the polymer was treated with acetic anhydride, which was free from acetic acid, in an amount of 10 parts by weight per part by weight of polymer in a test tube closed under vacuum. The sample tube was immersed in an oil bath heated to 170 ° C. and held there until the polymer had dissolved: 3-5 minutes were required with stirring.



   After the test tube had been cooled, the polymer precipitated with a yield in excess of 10%.



   In order to remove the polymer fraction which has not been doubly etherified, one can proceed in different ways.



   Thus, 1 part by weight of polymer was suspended in 20 parts of a 1 M aqueous solution of sodium carbonate and the suspension was heated to 1000 ° C. for 1 hour while stirring.



   This treatment mainly removes the polyoxymethylene glycols. After cooling, the polymer is recovered by filtering, washing with distilled water until the wash water reacts neutral and drying for 12 hours at 430C under a pressure of 15 mm Hg.



   The fraction obtained after this treatment by heating to 220 ° C. under vacuum for 1 hour shows a further weight loss with respect to the initial weight.



   Upon further heating to the same temperature, the remaining polymer appears to be indefinitely stable and its thermal stability was evaluated by the weight loss of the polymer by heating to 220 ° C. for 120 min in a glass kept under vacuum (residual pressure 10 mm Hg)
 EMI6.1
 Polymer mixed with 2oJo sodium carbonate is heated to 2200C in a glass test tube kept under vacuum.



   The amount of sodium carbonate mixed with the polymer is more than sufficient to neutralize any traces of acid that may be present.



   The stability of the polymer fraction obtained after this treatment, which consists of the polyoxymethylene dieters, is determined as stated above. 220
In this case too, the resulting polymer fraction has a value less than 0.1.
 EMI6.2
 

 <Desc / Clms Page number 7>

 
K: O less subject; the infrared absorption spectrum of a polymer film shows the almost complete disappearance of the absorption band at 2.9 f4, which is characteristic of the hydroxyl groups of the polyoxymethylene glycols, as can be seen from the attached diagram, spectrum B.



   Spectrum A was obtained with a lower thickness film in order to better show the spectrum zone between 8 and 12.



     Unless expressly stated otherwise, the dimensions given are to be understood as amounts by weight.



   Example 1 is taken as a comparative example in order to show the improvements achieved in the molecular weight and / or in the thermal stability of the polyoxymethylenes obtained in the examples.



     Example 1: 2 kg of one made from 548 g of polyoxymethylene and 1452 g of an aqueous solution with the following composition: water 70 wt.



   Formaldehyde 30% by weight suspension was filled into a 2 l reactor provided with a stirrer and immersed in a thermostatic bath at 350 ° C.



   The starting polyoxymethylene used in this experiment had the following properties:% red = 0.59 crystalline ortho-rhombic form, measured by X-ray = 80% residual fraction from the thermal treatment at 220 ° C. with Nazcas under vacuum = 0.



   The following substances were added every hour to the suspension having the stated composition after removing the same amount by weight of suspension:
50% strength by weight formaldehyde solution 28.0 g
10 n NaOH solution 1, 2 g
The amount of NaOH is sufficient to keep the pH of the suspension at about 10.4 during the entire reaction time.



   686 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, about 188 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was terminated after 31 days. The amount of polymer obtained daily remains practically constant.



   From the 14th day on, the polymer has almost constant properties, namely 71red = 0.28-0.30 crystalline ortho-rhombic shape 65 - 75%
Residual fraction from the thermal treatment at 2200C under vacuum with NaCO = O.



   Example 2: 2 kg of a suspension consisting of 304.8 g of polyoxymethylene and 1695.2 g of an aqueous solution of the following composition: HLjSO, -1.94%
Formaldehyde 40% was introduced into a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties:! ? red = 0.75 crystalline ortho-rhombic shape, measured radiographically = 76ça.



   The following substances were added every hour to the suspension with the stated composition after removing the same amount of suspension by weight:
50% strength by weight formaldehyde solution 27.7 g
 EMI7.1
 
676.3 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, about 103 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 24 days. The amount of polymer obtained daily is practically constant.



   From the 10th day on, the polymer has almost constant property values, namely:

 <Desc / Clms Page number 8>

   #red crystalline ortho-rhombic shape = 0%.



   Example 3: 2 kg of a suspension consisting of 390 g of polyoxymethylene and 1610 g of an aqueous solution of the following composition: H2SO4 4, 59%
Formaldehyde 35.5% was poured into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties:! ! red = 0.75 crystalline ortho-rhombic shape, measured radiographically = 76tao.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI8.1
 -% formaldehyde dissolvingUlg 2'7, 1 filtering, washing and drying 131 g of polyoxymethylene corresponding to 1.4 g of polymer per hour per 100 g of solid polymer introduced.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From the 7th day on, the polymer has almost constant property values, namely:!} Red = 0.15 crystalline ortho-rhombic shape = 25-351o.
 EMI8.2
 
4: filled.



   The starting polyoxymethylene used in this experiment had the following properties:
 EMI8.3
 
After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI8.4
 
Every 24 hours, 671.7 g of suspension were emptied from the reactor. After filtering, washing and drying this suspension, 143.8 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From the 7th day on, the polymer has almost constant property values, namely: '7red = 0.28 crystalline ortho-rhombic shape = 50-6010.
 EMI8.5
 were placed in a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties: 11 red = 0, 75 crystalline ortho-rhombic shape, measured by X-ray = 76%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:

 <Desc / Clms Page number 9>

 
 EMI9.1
 
670.3 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, about 150.9 g of polyoxymethylene, corresponding to 1.4 g of polymer per hour, were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From the 14th day on, the polymer has almost constant property values, namely:? ! red = 0. 62 crystalline ortho-rhombic shape = 70-75%.



   Example 6: 2 kg of a suspension consisting of 471.2 g polyoxymethylene and 1528.8 g of an aqueous solution of the following composition: H2SO 10, 68%
Formaldehyde 29% was poured into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35 ° C.



   The starting polyoxymethylene used in this experiment had the following properties: 7) rend = 0. 75 Crystalline ortho-rhombic shape, measured radiographically = 7f11 / 0
Residual fraction from the thermal treatment at 2200C under vacuum with Na, COs = 0
After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 25.6 g
96% strength by weight aqueous H2SO4 solution 2, 38 g
671.5 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, 158.2 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely: 11red = 0t65 crystalline ortho-rhombic shape = 70-80go doubly etherified residual fraction from the thermal treatment at 220 ° C. under vacuum
 EMI9.2
 
Example 7: 2 kg of a suspension consisting of 501.8 g of polyoxymethylene and 1498.2 g of an aqueous solution of the following composition:
 EMI9.3
 
Formaldehyde 26.5% was poured into a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 350C:
The starting polyoxymethylene used in this experiment had the following properties:

     li red = 0. 62 crystalline ortho-rhombic shape, measured radiographically = 80%.



   The following substances were added to the suspension with the stated composition
Removing the same amount by weight of suspension added every hour:
50% strength by weight CH2O solution 25.1 g
96% strength by weight aqueous H2SO4 solution 2.8 g
669.6 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, 168 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of solid polymer initially charged.



   The experiment was ended after 31 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely: 71red = 0.69 crystalline ortho-rhombic shape = 80-85%.

 <Desc / Clms Page number 10>

 
 EMI10.1
 kgefilled.



   The starting polyoxymethylene used in this experiment had the following properties: l1red = 0.62 crystalline ortho-rhombic shape, measured by X-ray = 80%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% by weight CHO solution 24.7 g
96 wt. -Ifige aqueous H2SO4 solution 3, 46 g
Every 24 hours, 675.8 g of suspension were emptied from the reactor. After filtering, washing and drying this suspension, about 179.9 g of polyoxymethylene, corresponding to 1.4 g of polymer per hour, were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 35 days. The amount of polymer obtained daily is practically constant. From the 17th day on, the polymer has almost constant property values, namely: #red = 0.60 crystalline ortho-rhombic shape = 80-85%.



   Example 9: 2 kg of a suspension consisting of 561.3 g of polyoxymethylene and 1438.7 g of one
 EMI10.2
 : filled.



   The starting polyoxymethylene used in this experiment had the following properties: T! red = 0. Crystalline ortho-rhombic shape, measured radiographically = 80%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI10.3
 Filtration, washing and drying 187.2 g of polyoxymethylene corresponding to 1.4 g of polymer per hour per 100 g of initially charged solid polymer are obtained.



   The experiment was ended after 31 days. The amount of polymer received daily is practical
 EMI10.4
 : filled.



   The starting polyoxymethylene used in this experiment had the following properties:
 EMI10.5
 



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 23.5 g
96% strength by weight aqueous H2SO4 solution 4.55 g

 <Desc / Clms Page number 11>

 
Every 24 hours, 673.2 g of suspension were emptied from the reactor. From this suspension, after filtering, washing and drying, 182.5 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 7th day on, the polymer has almost constant property values, namely: 1fred = 0.51 crystalline ortho-rhombic shape = 65-75%.
 EMI11.1
 filled.



   The starting polyoxymethylene used in this experiment had the following properties:! ? red = 0.62 crystalline ortho-rhombic shape, measured radiographically = 800/0.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50 wt. ige CH2O solution 22.0 g
96% strength by weight aqueous HSO solution 6, 13 g
Every 24 hours, 675.1 g of suspension were emptied from the reactor. From this suspension, after filtration, washing and drying, 197 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of solid polymer initially charged.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 7th day on, the polymer has almost constant property values, namely: #red = 0.24 crystalline ortho-rhombic shape = 30 - 350/0.



   Example 12: 2 kg of a suspension consisting of 528, 1 g of polyoxymethylene and 1471.9 g of a
 EMI11.2
 : Formaldehyde 10 0/0 was introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties: 71red = 0.62 crystalline ortho-rhombic shape, measured by X-ray = 80lao.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% by weight CI O solution 18.9 g
96% by weight aqueous H2SO4 solution 9.08 g
671.5 g of suspension were emptied from the reactor every 24 hours. From this suspension, after filtration, washing and drying, 177.3 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 17 days. The amount of polymer obtained daily is practically constant. From about the 7th day on, the polymer has almost constant property values, namely:? ! red <0.1 crystalline ortho-rhombic form = 0%.



   Example 13: 2 kg of a suspension consisting of 265.2 g of polyoxymethylene and 1734.8 g of an aqueous solution of the following composition: p-toluenesulfonic acid 4, 2910
40% formaldehyde was introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties
 EMI11.3
 

 <Desc / Clms Page number 12>

 
 EMI12.1
 

 <Desc / Clms Page number 13>

 doubly etherified residual fraction from the thermal treatment at 2200C under vacuum with Na2CQ, = 10-15%
 EMI13.1
 



     Example 16: 2 kg of a suspension consisting of 343 g of polyoxymethylene and 1657 g of an aqueous solution of the following composition: HC104 6.4910
Formaldehyde 35% was introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35 ° C.



   The starting polyoxymethylene used in this experiment had the following properties:
 EMI13.2
 



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 25.83 g
70% strength by weight aqueous HClO4 solution 2, 16 g
Every 24 hours, 671.8 g of suspension were emptied from the reactor. After filtering, washing and drying this suspension, 115.2 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely: #red = 0.37 crystalline ortho-rhombic shape = 76 - 82je.
 EMI13.3
 were placed in a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties: 1 / red = 0.75 crystalline ortho-rhombic shape, measured by X-ray = 76%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 24.82 g
70 wt. ige aqueous HCl04 solution 3.04 g
668.7 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, 115.1 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely: 1 / rend = 0.56 crystalline ortho-rhombic shape = 87-92%.



     Example 18: 2kg of a suspension consisting of 342.6 g polyoxymethylene and 1657.4 g of an aqueous solution of the following composition:
 EMI13.4
 
Formaldehyde 31 0/0 was introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties: n red = 0.75 crystalline ortho-rhombic shape, measured X-ray = 76%

 <Desc / Clms Page number 14>

 
Residual fraction from the thermal treatment at 2200C under vacuum with Na2CO3 = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 23.98 g
 EMI14.1
 
672 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, 115.1 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer received daily is practical
 EMI14.2
 were placed in a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties: '7red = 0.75 crystalline ortho-rhombic shape, measured by X-ray = 76vis.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the composition mentioned: 50% by weight CH2O solution 22.45 g 70% by weight aqueous HClO4 solution 5, 61 g
Every 24 hours, 673.4 g of suspension were emptied from the reactor. From this suspension, after filtering, washing and drying, 119.4 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely: 11red = 0. 50 crystalline ortho-rhombic shape = 56-62%.
 EMI14.3
 
20: filled.



   The starting polyoxymethylene used in this experiment had the following properties: 11red = 0.75 crystalline ortho-rhombic shape, measured by X-ray = 76%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 21.2 g
 EMI14.4
 Filtration, washing and drying 112, 8 g of polyoxymethylene corresponding to 1.4 g of polymer per hour per 100 g of initially charged solid polymer are obtained.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely:

 <Desc / Clms Page number 15>

 71red = 0.35 crystalline ortho-rhombic form = 50-55%).
 EMI15.1
 
21: filled.



   The starting polyoxymethylene used in this experiment had the following properties:? ! red = 0. 62 Crystalline ortho-rhombic shape, measured radiographically = 82%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI15.2
 
668.6 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, 127.2 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 26 days. The amount of polymer obtained daily is practically constant. From the 9th day on, the polymer has almost constant property values, namely: 11 red = 0.27 crystalline ortho-rhombic shape = 55-65%.



   Example 22: 2 kg of a suspension consisting of 345.2 g polyoxymethylene and 1654.8 g of an aqueous solution of the following composition:
HCl 6%
Formaldehyde 31% was poured into a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.
 EMI15.3
 
665 g of suspension were emptied from the reactor every 24 hours. From this suspension, after filtration, washing and drying, 113 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of solid polymer initially charged.



   The experiment was ended after 30 days. The amount of polymer obtained daily is practically constant. From about the 10th day on, the polymer has almost constant property values, namely: 71 red = 0.59 crystalline ortho-rhombic form> 90%.
 EMI15.4
 were placed in a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties:? ! red = 0.75 crystalline ortho-rhombic shape, measured radiographically = 76%.



   Residual fraction from the thermal treatment at 2200C under vacuum with NaCCL = O.



   The following substances were added to the suspension with the stated composition

 <Desc / Clms Page number 16>

   Removal of the same amount by weight of suspension added hourly: 50% strength by weight CH2O solution 22.4 g 35 gel. Doed aqueous HCl solution 5.4 g. 665 g suspension were emptied from the reactor every 24 hours. From this suspension, after filtering, washing and drying, 104 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of solid polymer initially charged.



  The experiment was ended after 33 days. The amount of polymer obtained daily is practically constant. From about the 13th day the polymer has almost constant property values, namely: 71red = 0.56 crystalline ortho-rhombic form> 90% doubly etherified residual fraction from the thermal treatment at 2200C under vacuum with Na2CO3 = 10-15go
 EMI16.1
 aqueous solution of the following composition:
HCl 13.2%
20.0% formaldehyde was introduced into a 2 liter reactor equipped with a stirrer and immersed in a thermostatic bath at 35.degree.



   The starting polyoxymethylene used in this experiment had the following properties: 71red = 0.62 crystalline ortho-rhombic shape, measured by X-ray = 82%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50 wt. ige CH20 solution 19.4 g
35% strength by weight aqueous HCl solution, 8.7 g
Every 24 hours, 674.4 g of suspension were emptied from the reactor. After filtering, washing and drying this suspension, 122.2 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of initially charged solid polymer.



   The experiment was ended after 29 days. The amount of polymer received daily is practical
 EMI16.2
 were placed in a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35 ° C.



   The starting polyoxymethylene used in this experiment had the following properties: 71red = 0.75 crystalline ortho-rhombic shape, measured by X-ray = 76%.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
50% strength by weight CH2O solution 25.3 g
96% by weight aqueous H SQ. Solution 2.8 g
675 g of suspension were emptied from the reactor every 24 hours. After filtering, washing and drying this suspension, 202 g of polyoxymethylene corresponding to 1.4 g of polymer per hour were obtained per 100 g of solid polymer initially charged.



   The experiment was ended after 29 days. The amount of polymer obtained daily is practically constant. From the 13th day on, the polymer has almost constant property values, namely: n red = 0.85 crystalline ortho-rhombic shape = 65-75%.

 <Desc / Clms Page number 17>

 



     Example 26: 2 kg of a suspension consisting of 244.3 g of polyoxymethylene and 1755.7 g of a solution with the following composition:
 EMI17.1
 
<tb>
<tb> Hui <SEP> 270 <SEP>
<tb> CHOH <SEP> 9% <SEP>
<tb> CH20 <SEP> 38% <SEP>
<tb>
 were placed in a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath of 35uC.



   The starting polyoxymethylene used in this experiment had the following properties:?) Red = 0.58 crystalline ortho-rhombic shape = 89%
Residual fraction from the thermal treatment at 2200C under vacuum with Na COs = 0.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI17.2
 
<tb>
<tb> äu <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 25.3 <SEP> g
<tb> 37 <SEP> by weight <SEP> aqueous <SEP> HCl solution <SEP> 1, <SEP> 27 <SEP> g
<tb> Methanol <SEP> (99 <SEP>% strength by weight) <SEP> 1. <SEP> 17 <SEP> g
<tb>
 
666 g of suspension were emptied from the reactor every 24 hours. 80 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 35 days. The amount of polymer obtained daily is practically constant. From about the 24th day the polymer has almost constant property values, namely: #red = 0.36 crystalline ortho-rhombic shape = 75-85% doubly etherified residual fraction from the thermal treatment at 220 C under vacuum with Na2CO3 = 15-25 %
 EMI17.3
 
 EMI17.4
 
<tb>
<tb> dHCl <SEP> 4%
<tb> CH3OH <SEP> 5%
<tb> formaldehyde <SEP> 371o
<tb>
 were placed in a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties: 17 red = 0.58 crystalline ortho-rhombic shape = 89%
Residual fraction from the thermal treatment at 2200C under vacuum with NaCO = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI17.5
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH20 solution <SEP> 23.7 <SEP> g
<tb> 37 <SEP>% by weight <SEP> aqueous <SEP> HCl solution <SEP> 2, <SEP> 5 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99% <SEP> 1, <SEP> 18 <SEP> g
<tb>
 
657 g of suspension were emptied from the reactor every 24 hours. About 60 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 40 days. The amount of polymer received daily is practical
 EMI17.6
 

 <Desc / Clms Page number 18>

 
 EMI18.1
 
<tb>
<tb>: CRC <SEP> 33% <SEP>
<tb> CH3OH <SEP> 2%
<tb> HCl <SEP> 6%
<tb>
 were introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath of oc.



   The starting polyoxymethylene used in this experiment had the following properties: #red = 0. 58 crystalline ortho-rhombic shape = 89No
Residual fraction from the thermal treatment at 2200C under vacuum with Na2CO3 = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI18.2
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 23, <SEP> 2 <SEP> g
<tb> 37 <SEP>% by weight <SEP> aqueous <SEP> HCl solution <SEP> 3.78 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP>% by weight <SEP> 0.466 <SEP> g
<tb>
 
657 g of suspension were emptied from the reactor every 24 hours. About 88 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 30 days. The amount of polymer received daily is practical
 EMI18.3
 
 EMI18.4
 
<tb>
<tb>: HCl <SEP> tfyo
<tb> CH, <SEP> OH <SEP> 8% <SEP>
<tb> formaldehyde <SEP> 35%
<tb>
 were introduced into a S l reactor equipped with a stirrer and immersed in a thermostatic bath at 35 ° C.



   The starting polyoxymethylene used in this experiment had the following properties: # red = 0. 58 Crystalline ortho-rhombic shape, measured by X-ray zo
Residual fraction from the thermal treatment at 2200C under vacuum with Na2CO3 = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI18.5
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 21.5 <SEP> g
<tb> 37 <SEP> by weight <SEP> aqueous <SEP> HCl solution <SEP> 4.2 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> s <SEP>: <SEP> 99 <SEP>% by weight <SEP> 2.1 <SEP> g
<tb>
 
About 665 g of suspension were emptied from the reactor every 24 hours. From this suspension were after filtration. Washing and drying obtained about 35 g of polymer.



   The experiment was ended after 24 days. The amount of polymer received daily is practical
 EMI18.6
 : Example 30: 2 kg of a suspension consisting of 217.8 g of polyoxymethylene and 1782. 2 g of a solution of the following composition:
 EMI18.7
 
<tb>
<tb> HCl <SEP> 4%
<tb> CH, <SEP> OH <SEP> 5% <SEP>
<tb> NaCl <SEP> 10%
<tb> formaldehyde <SEP> 31%
<tb>
 

 <Desc / Clms Page number 19>

 were introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35.degree.



   The starting polyoxymethylene used in this experiment had the following properties: tred = 0. 58 crystalline ortho-rhombic form, measured by radiography = 891o
Residual fraction from the thermal treatment at 220 C under vacuum with Nazcas = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI19.1
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 21, <SEP> 2 <SEP> g
<tb> 37 <SEP>% by weight <SEP> aqueous <SEP> HCl solution <SEP> 2. <SEP> 7 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP> wt .-% <SEP> 1, <SEP> 2 <SEP> g
<tb> powdered <SEP> NaCl <SEP> 2. <SEP> 5 <SEP> g
<tb>
 
About 660 g of suspension were emptied from the reactor every 24 hours. About 70 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 30 days. The amount of polymer received daily is practical
 EMI19.2
 
 EMI19.3
 
<tb>
<tb>: HCI <SEP> 5, <SEP> 4%
<tb> CH, <SEP> OH <SEP> 5. <SEP> 4% <SEP>
<tb> CH2O <SEP> 28 <SEP>%
<tb> NaCl <SEP> 8. <SEP> 30/0 <SEP>
<tb>
 
 EMI19.4
 
350C filled.



   The starting polyoxymethylene used in this experiment had the following properties: # = 0. 58 crystalline ortho-rhombic shape, measured by X-ray = 89%
Residual fraction from the thermal treatment at 2200C under vacuum with Nazcas = O.



   The following substances were added to the suspension with the stated composition
 EMI19.5
 
 EMI19.6
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 21, <SEP> 6 <SEP> g
<tb> 37 <SEP> by weight <SEP> aqueous <SEP> HCl solution <SEP> 3.6 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP>% by weight <SEP> l. <SEP> 31 <SEP> g
<tb> NaCl powder <SEP> 2.03 <SEP> g
<tb>
 
About 682 g of suspension were drained from the reactor every 24 hours. About 90 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 40 days. The amount of polymer obtained daily is practically constant. From about the 25th day on, the polymer has almost constant property values, namely: 71rend = 0.30
 EMI19.7
 
 EMI19.8
 
<tb>
<tb> 950/0HCl <SEP> 5.4%
<tb> CH3OH <SEP> 5, <SEP> 4%
<tb>
 

 <Desc / Clms Page number 20>

 
 EMI20.1
 
<tb>
<tb> CHO <SEP> 28 <SEP>% <SEP>
<tb> KCl <SEP> 8. <SEP> 3o <SEP>
<tb>
 
 EMI20.2
 filled.



   The starting polyoxymethylene used in this experiment had the following properties:
 EMI20.3
 
Residual fraction from the thermal treatment at 2200C under vacuum with a2CO -0.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI20.4
 
<tb>
<tb> 50 <SEP> gel. <SEP> doigte <SEP> aqueous <SEP> CH2O solution <SEP> 21, <SEP> 5 <SEP> g
<tb> 37 <SEP>% by weight <SEP> aqueous <SEP> HCl solution <SEP> 3. <SEP> 6 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP> wt .-% <SEP> l, <SEP> 3 <SEP> g
<tb> KCl powder <SEP> 2, <SEP> 0 <SEP> g
<tb>
 
 EMI20.5
 Filtering, washing and drying obtained about 90 g of polymer.



   The experiment was ended after 42 days. The amount of polymer received daily is practical
 EMI20.6
    : 7) red = 0. 55 and an ortho-rhombic crystallinity of 85%, measured by X-ray, and a solution of the following composition:
 EMI20.7
 
<tb>
<tb> H2SO4 <SEP> 229.5 <SEP> g <SEP> (11%)
<tb> CH3OH <SEP> 146, <SEP> 0 <SEP> g <SEP> (<SEP> 7%)
<tb> Cl \ O <SEP> 667. <SEP> 0 <SEP> g <SEP> (32%)
<tb> HO <SEP> 1042.5 <SEP> g <SEP> (50%)
<tb>
 were filled into a 3 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35uC.



   After removing the same amount by weight of suspension, the following substances were added every 2 hours to the suspension with the stated composition:
 EMI20.8
 
<tb>
<tb> 57 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 66.8 <SEP> g
<tb> 96 <SEP> by weight <SEP> aqueous <SEP> H <SEP> SO "<SEP> solution <SEP> 6, <SEP> 7 <SEP> g
<tb> 99.9 <SEP>% by weight <SEP> methanol <SEP> 4, <SEP> 1 <SEP> g
<tb>
 
About 935 g of suspension were emptied from the reactor every 24 hours. About 223 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 35 days. The amount of polymer obtained daily is practically constant.



   When the system is under stationary conditions, the polymer has the following properties: 1) red = 0.55 crystalline ortho-rhombic form zoo
If the product is subjected to treatment with a 1 M sodium carbonate solution at 100 ° C. for 1 hour, a weight loss of 25% by weight occurs.



   With a further treatment until it melts at 220 ° C. under vacuum for 20 minutes, it suffers a further loss of 250/0, based on the initial weight.



   The characteristics of the remaining products are:
 EMI20.9
 

 <Desc / Clms Page number 21>

 
 EMI21.1
 
 EMI21.2
 
<tb>
<tb>? <SEP> redHjSO <SEP> 9, <SEP> 6%
<tb> CH, <SEP> OH <SEP> 6 <SEP> 0/0
<tb> formaldehyde <SEP> 32 <SEP>%
<tb>
 were introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35.degree.



   The starting polyoxymethylene used in this experiment had the following properties: 71red = 0.78 crystalline ortho-rhombic shape, measured by X-ray = 76
After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI21.3
 
<tb>
<tb> au <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 24.4 <SEP> g
<tb> 96 <SEP> by weight <SEP> aqueous <SEP> HzS04 solution <SEP> 2, <SEP> 2 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP> wt .-% <SEP> 1, <SEP> 49 <SEP> g
<tb>
 
About 676 g of suspension were emptied from the reactor every 24 hours. About 100 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 29 days. The amount of polymer obtained daily is practically constant. After about 15 days, the polymer had almost constant property values, namely: # red = 0. 6 crystalline ortho-rhombic shape 2 95%
If the product is subjected to a treatment with sodium carbonate solution, it loses 35-45% of its weight.



   The subsequent treatment in vacuum until melting at 2200C causes another
 EMI21.4
 
 EMI21.5
 
<tb>
<tb> dnu <SEP> 29%
<tb> CH3OH <SEP> 7%
<tb> H2O <SEP> 49% <SEP>
<tb> H2SO4 <SEP> 15%
<tb>
 
 EMI21.6
 filled.



   The starting polyoxymethylene used in this experiment had the following properties: 7) red = 0. 60 crystalline ortho-rhombic shape = 891o
The following substances were added every hour to the suspension with the stated composition after removing the same amount by weight of suspension
 EMI21.7
 
<tb>
<tb> ob, <SEP> z <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 31.35 <SEP> g
<tb> 96 <SEP> by weight <SEP> aqueous <SEP> H2SO4 solution <SEP> 4, <SEP> 56 <SEP> g
<tb> 99. <SEP> 9 <SEP> mixed <SEP> methanol <SEP> 2, <SEP> 04 <SEP> g <SEP>
<tb>
 
934 g of suspension were emptied from the reactor every 24 hours.

   About 233 g of polymer were obtained from this suspension after filtering, washing and drying.
 EMI21.8
 
If the product is subjected to a treatment with a 1 M sodium carbonate solution for 1 hour at 1000C, it loses 15% of its weight.



   The subsequent treatment in a vacuum for 20 minutes to melt it at 220 C causes a further weight loss of 30%, based on the initial weight:
The properties of the residual polymer are:

 <Desc / Clms Page number 22>

 
 EMI22.1
 d <1. O. filled.



   The starting polyoxymethylene used in this experiment had the following properties: 11red = 0.78 crystalline ortho-rhombic shape, measured by X-ray = 76via
Residual fraction from the thermal treatment at 2200C in a vacuum with NaCO = 0.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI22.2
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 11. <SEP> 23 <SEP> g
<tb> 70 <SEP>% by weight <SEP> aqueous <SEP> HCIO solution <SEP> 1, <SEP> 88 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP>% by weight <SEP> 0.86 <SEP> g
<tb>
 
About 331 g of suspension were emptied from the reactor every 24 hours. About 30 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 34 days. The amount of polymer received daily is practical
 EMI22.3
 
 EMI22.4
 
<tb>
<tb>: HClO <SEP> 9, <SEP> 8% <SEP>
<tb> CH3OH <SEP> 13 <SEP>%
<tb> Formaldehyde <SEP> 35 <SEP> 0/0
<tb>
 were placed in a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35 ° C.



   The starting polyoxymethylene used in this experiment had the following properties:
 EMI22.5
 
Residual fraction from the thermal treatment at 2200C in a vacuum with Nazcas = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI22.6
 
<tb>
<tb> ou <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 4.68 <SEP> g
<tb> 70 <SEP> by weight <SEP> aqueous <SEP> HClO4 solution <SEP> 0.68 <SEP> g
<tb> Methanol <SEP> with <SEP> of a <SEP> purity <SEP> s <SEP>: <SEP> 99 <SEP>% by weight <SEP> 0.64g
<tb>
 
144 g of suspension were emptied from the reactor every 24 hours. About 24 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 40 days. The amount of polymer obtained daily is practically constant. From about the 30th day on, the polymer has almost constant property values, namely: lured = 0. 45
 EMI22.7
 

 <Desc / Clms Page number 23>

 
 EMI23.1
 
<tb>
<tb> ortho-rhombic <SEP> form> <SEP> 900 / 0HC1 <SEP> 7. <SEP> 2 <SEP>
<tb> CH3OH <SEP> 6.5%
<tb> CH2O <SEP> 33 <SEP>%
<tb>
 were introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35.degree.



   The starting polyoxymethylene used in this experiment had the following properties: trend = 0. 75 crystalline ortho-rhombic shape, measured by radiography = 75%
Residual fraction from the thermal treatment at 2200C in vacuo with Na, COs = O.



   After removing the same amount by weight of suspension, the following substances were added every hour to the suspension with the stated composition:
 EMI23.2
 
<tb>
<tb> 60 <SEP> by weight <SEP> aqueous <SEP> CH2O solution <SEP> 15, <SEP> 8 <SEP> g
<tb> 35 <SEP>% by weight <SEP> aqueous <SEP> HCl solution <SEP> 3, <SEP> 23 <SEP> g
<tb> Methanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP> wt .-% <SEP> 1, <SEP> 02 <SEP> g
<tb>
 
About 480 g of suspension were emptied from the reactor every 24 hours. from this suspension were after filtration. Washing and drying obtained about 100 g of polymer.



   The experiment was ended after 33 days. The amount of polymer obtained daily is practically constant.



   After about 13 days, the polymer has almost constant property values, namely: lured = 0.40 crystalline ortho-rhombic form> 85% doubly etherified residual fraction from the thermal treatment at 2200C under vacuum with NCo = 30-400 / 0
 EMI23.3
 
 EMI23.4
 
<tb>
<tb> 39 <SEP>: <SEP> H2SO4 <SEP> 229.5 <SEP> g
<tb> C2H5OH <SEP> 146.0 <SEP> g
<tb> CH2O <SEP> 646. <SEP> 5 <SEP> g <SEP>
<tb> H20 <SEP> 1063, <SEP> 0 <SEP> g
<tb>
 were placed in a 3 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35 ° C.



   The starting polyoxymethylene used in this experiment had the following properties:? ! red = 0. 55 crystalline ortho-rhombic form, measured by radiography = 85%
After removing the same amount by weight of suspension, the following substances were added every 2 hours to the suspension with the stated composition:
 EMI23.5
 
<tb>
<tb> 56.2 <SEP> wt .-% <SEP> ige <SEP> aqueous <SEP> CH2O solution <SEP> 66.84 <SEP> g
<tb> 96 <SEP> wt .-% <SEP> ige <SEP> aqueous <SEP> H2SO4 solution <SEP> 6, <SEP> 70 <SEP> g
<tb> 95 <SEP>% by weight <SEP> ethanol <SEP> 4.30 <SEP> g
<tb>
 
About 934 g of suspension were emptied from the reactor every 24 hours. About 233.5 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 20 days. The amount of polymer obtained daily is practically constant.



   If the product is subjected to a treatment with the above sodium carbonate solution at 1000 ° C. for 2 hours, it loses 50% of its weight.



   The subsequent treatment in a vacuum at 220 ° C. for 15-20 min to melt it causes a further weight loss of 25%. based on the initial weight.
 EMI23.6
 : Example 40: 2 kg of a suspension consisting of 308.4 g of polyoxymethylene and 1691.6 g of a solution with the following composition:

 <Desc / Clms Page number 24>

 
 EMI24.1
 
<tb>
<tb> HSO <SEP> 9. <SEP> 5%
<tb> CH3CH2CH2OH <SEP> 6 <SEP> 0/0
<tb> formaldehyde <SEP> 33 <SEP>%
<tb>
 were placed in a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 350C.



   The starting polyoxymethylene used in this experiment had the following properties:
 EMI24.2
 
 EMI24.3
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 10. <SEP> 4 <SEP> g
<tb> 96 <SEP>% by weight <SEP> aqueous <SEP> H2SO4 solution <SEP> 1.01 <SEP> g
<tb> n-propanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 98 <SEP> weight <SEP> -0/0 <SEP> 0.62 <SEP> g
<tb>
 
About 288 g of suspension were emptied from the reactor every 24 hours. About 44 g of polymer were obtained from this suspension after filtering, washing and drying.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant.



   After 15 days the polymer has almost constant property values. namely: 71red = 0. 40 crystalline ortho-rhombic form> 75% doubly etherified residual fraction (from treatment with Na2CO3 at 220 C) = 10 - 20%
 EMI24.4
 
 EMI24.5
 
<tb>
<tb> twice <SEP> etherified <SEP> residual fraction H2SO4 <SEP> Y, <SEP> bozo <SEP>
<tb> CH3CH2CH2CH2OH <SEP> 6 <SEP>%
<tb> formaldehyde <SEP> 31 <SEP>%
<tb>
 were introduced into a 2 l reactor equipped with a stirrer and immersed in a thermostatic bath at 35.degree.



   The starting polyoxymethylene used in this experiment had the following properties:? ! red = 0.59 crystalline ortho-rhombic shape = 681o
Residual fraction from the thermal treatment at 2200C with nazis in a vacuum = O.



   The following substances were added every hour to the suspension with the stated composition after removing the same amount by weight of suspension:
 EMI24.6
 
<tb>
<tb> 50 <SEP>% by weight <SEP> aqueous <SEP> CH2O solution <SEP> 10. <SEP> 4 <SEP> g
<tb> 96 <SEP> by weight <SEP> aqueous <SEP> H2SO4 solution <SEP> 0. <SEP> 97 <SEP> g
<tb> n-butanol <SEP> with <SEP> a <SEP> purity <SEP> of <SEP> 99 <SEP>% by weight <SEP> 0, <SEP> 59 <SEP> g
<tb>
 
About 287 g of suspension were emptied from the reactor every 24 hours. From this suspension, about 51.4 g of polymer were obtained after filtering, washing and drying.



   The experiment was ended after 28 days. The amount of polymer obtained daily is practically constant.

** WARNING ** End of DESC field may overlap beginning of CLMS **.

 

Claims (1)

After about 15 days the polymer has almost constant property values, namely: 17red = 0.38 crystalline ortho-rhombic form (measured by X-ray)> 50% doubly etherified residual fraction from the thermal treatment at 2200C with NaCO = 5 - 15% EMI24.7 etherified residual fraction 1. Process for the production of formaldehyde high polymers with high thermal stability by either continuous or intermittent supply of a concentrated aqueous formaldehyde solution to <Desc / Clms Page number 25> a suspension of a solid polyoxymethylene obtained in any way in an aqueous formaldehyde solution with a CHO concentration which is between the equilibrium concentration and the EMI25.1 Waiting for one or more strong organic or inorganic acids with a pKa <2 for each hydrogen atom, the concentration of which in the aqueous solution is kept between 0.5 and 31% by weight of the solution. 2. The method according to claim l, characterized in that the polymerization of the formaldehyde is carried out in the presence of one or more aliphatic alcohols. whose concentration in the liquid phase is kept at a value below 25% by weight of the solution. 3. The method according to claim 2, characterized. that methanol is used as the alcohol. EMI25.2 of a salt (with a neutral reaction in water) of an inorganic base with a strong organic or inorganic acid with a pKa <2 for each hydrogen atom, the concentration of which in the solution is kept at a value which is less than or equal to the saturation concentration of the system .