DE1770427A1 - Process for the production of modified polyvinyl alcohol molded bodies - Google Patents

Description

21 Kurashiki Hayon Co., Ltd., Kurashiki City (Japan)

Process for the production of modified polyvinyl alcohol

moldings

The invention relates to a process for the production of modified polyvinyl alcohol moldings. The aim of the invention is to produce modified polyvinyl alcohol moldings with a high utility value to create that are excellent water-resistant, pliable and resistant to organic Solvents are.

Because polyvinyl alcohols have melting points that are above their decomposition temperatures, they are for the Shaping by melt extrusion not suitable. That's why Up until now, one usually has an aqueous solution with a Polyvinyl alcohol concentration of up to 60% is used and films or other shaped bodies are produced therefrom in the wet or dry process. This procedure is not very special economical because of the large amount of heat and an additional device in addition to the dissolution of the polyvinyl alcohols

- 2 - ~

209818/0830

required for evaporation of the water after shaping are. In addition, longer drying times are required, and uniform drying is difficult to carry out, especially when manufacturing thick bodies such as Plates or tubes.

Another technique used so far is to use polyvinyl alcohol to be used in which 75 to 9ü mol% of the acetyl groups of the polyvinyl acetate are substituted by hydroxyl groups, and these polyvinyl alcohol in the presence of large To subject quantities of plasticizer to melt deformation. Again, this process is therefore not economical, because the molded articles obtained are poor in water resistance point.

Under these circumstances, no way of taking advantage of the favorable properties has yet been investigated of polyvinyl alcohols, i.e. the excellent resistance to organic compounds such as straight-chain, branched, aromatic and halogenated hydrocarbons, can be exploited.

The present invention eliminates the disadvantages outlined above. The method of manufacture of modified polyvinyl alcohol moldings according to Invention is characterized in that a copolymer of vinyl acetate and one or more saturated, branched Fatty acid vinyl esters of the general formula

209818/0830

CH, = eiIOCOCR .. R ₀ K, -,

in which K ₁ to it., alkyl groups are saponified, and that the polyvinyl alcohol modified in this way is spun in the presence or absence of a plasticizer in a melt or semi-melt process.

In the method of the invention, those are modified Polyvinyl alcohols with saturated branched acyl groups are extremely water-resistant and flexible against ordinary ones Polyvinyl alcohols ^ and also they have a significantly reduced softening point, so that they with or can be shaped by melt or semi-melt extrusion without the addition of a plasticizer. Because of that After extrusion no drying is required, it is possible to produce films, tubes and other molded articles with high Establish value in use.

It is usually the case with modified polyvinyl alcohols long straight ± tetti £> e have saturated acyl groups, too expect them to be internally softened to some extent. iJies has been published in, for example, Journal of Polymer Science ", .32, (1958), page 33. In this work the internal plasticizer effect of a modified i-olyvinyl alcohol containing stearyl side chains was investigated and that by hydrolysis of only highly saponifiable Formy! Ester groups in copolymers of vinyl formate and Vinyl stearate is made to vinyl alcohol groups. This

209818/0830 - 4 -

However, the process is not useful for industry because it is based on the use of vinyl formate, which as a monomer is extremely unstable and too easy to saponify.

Another possibility has been investigated, one to produce similarly modified polyvinyl alcohol, in which vinyl ester of a saturated fatty acid is assumed with a number of carbon atoms greater than that of vinyl acetate as fatty acid vinyl ester, and which is saponified to vinyl alcohol. However, the conditions under which the saturated fatty acid vinyl ester with more carbon atoms than vinyl acetate is saponified to saponify the saturated long straight-chain acyl groups, so that it is impossible to use an internally plasticized modified To obtain polyvinyl alcohol, which is suitable for processing into molded articles with the desired properties.

According to the invention, the aim was to provide a method for production one inside. plasticized / modified polyvinyl alcohols to create that can be processed into moldings. During these examinations it was found that daia a modified polyvinyl alcohol obtained by saponification of a Copolymer of vinyl acetate and a saturated branched fatty acid vinyl ester is excellent is internally plasticized and that it has a very excellent resistance to organic solvents, is contractual and essential to plasticizers

09818/0 630

is better deformable in the melt process than the modified polyvinyl alcohols with saturated polyvinyl alcohols described above straight chain acyl groups.

The attached file is used for a better understanding of the invention Drawing graphing the melt viscosity values of the various modified polyvinyl alcohols are.

The drawing shows the viscosity values of the polyvinyl alcohols modified according to the invention at 200 ° C. as a graph shown. As can be seen from the diagram, it has lower viscosity values and better extrusion properties as modified polyvinyl alcohol with saturated straight-chain acyl groups * referred to in the diagram Curve 1 is a mixture of 100 parts of modified polyvinyl alcohol with 5 mol% of saturated straight-chain acyl groups and 20 parts of trimethylolpropane as a plasticizer. Curve 2 denotes

net a mixture of 100 parts of modified polyvinyl alcohol with 5 mol% of saturated branched acyl groups and 20 parts of trimethylolpropane. Curve 3 denotes a mixture of 100 parts of modified polyvinyl alcohol with 7 mol% of saturated branched acyl groups and 20 parts of trimethylolpropane. The ordinate denotes the natural logarithm of the viscosity Va (poise) and the abscissa the natural

ir '

—1 logarithm of the pushing speed (see).

■ - 6 -

209818/0830

As can be seen from Table 1, which shows the flocculation temperatures of polyvinyl alcohol and two types of modified polyvinyl alcohols with different plasticizers, lower temperatures were found for modified polyvinyl alcohol with saturated branched acyl groups, at which the polymer precipitated out of the plasticizer solutions, and that it compared with cten plasticizers is significantly better tolerated than fully saponified polyvinyl alcohol and than modified polyvinyl alcohol with saturated straight-chain acyl groups. This means that in the case of molded articles made of modified polyvinyl alcohol according to the invention, even if they contain a large amount of plasticizer, this does not migrate in an undesirable manner at high temperature and relative humidity. Moldings made of completely saponified polyvinyl alcohol, of modified polyvinyl alcohol with 5 mol% of saturated straight-chain acyl groups and of modified polyvinyl alcohol with 5 mol- ¹ ; Saturated branched acyl groups each containing 40 parts of trimethylolpropane as plasticizer show, when kept under a condition of 40 ° C. and a relative humidity of 90%, that the former two have considerable plasticizer migration, while this is the case with the latter molded body is not the case at all.

- 7-

209818/0830

Table 1

Plasticizers

Polymer

Fully modified modified saponified polyvinylal- polyvinyl-polyvinyl- alcohol No. 1 alcohol No. alcohol ( ⁰ C) ( ⁰ C) ( ⁰ C)

Glycerin 113 insoluble 115 i, 4-.dutanediol 147 114 71 1,3-butanediol 156 103 87 Diethylene glycol 153 97 Ö4 Triethylene glycol insoluble 129 109 Propylene glycol 140 56 <30 Dipropylene glycol insoluble 139 129 Diethanolamine lib - - Triethanolamine insoluble 104 65 ^ -Caprolactam 80 38 40

Notes: 1) The flocculation temperature was determined

putting each polymer together with a plasticizer at a polymer concentration of 10 Vo was heated and dissolved, after which the melt at a ratio of 3 ° C / min was cooled until the polymer began to precipitate, this point being the flocculation temperature the particular mixture was designated.

2) The modified polyvinyl alcohol is No. 1

one with 5 iiiol-Vo straight-chain acyl-209818/0830

groups (Peieirgonyigruijpen), and the modified i-oiyvinylaikoliol No. 2 is a modified 1 vinyl alcohol with 5 Mo1- / u branched alkyl groups (1,1-3,3-tetrainethylbutanecarboxyl groups) according to the invention,

The modified polyvinyl alcohols according to the invention are prepared by copolymerizing vinyl acetate and a saturated branched fatty acid vinyl ester, after which the copolymer obtained is saponified in the usual way. This process is characterized in that, in contrast to saturated straight-chain fatty acid esters, the saturated branched fatty acid vinyl esters have a higher resistance to alkali than vinyl acetate, and therefore the branched fatty acid ester groups are not saponified even under conditions which allow the saponification of the liquid ester groups. However, they remain in the polymer.

In the present invention it is not appropriate to use fatty acid vinyl esters other than vinyl acetate, ie vinyl formate, vinyl propionate or n-vinyl ethyl acetate. Vinyl formate is unsuitable because the lionomer is unstable and cannot be copolymerized with a saturated branched fatty acid vinyl ester to give a product with a sufficiently high degree of polymerization that can be extruded. It was also found that saturated joradkcttij.ye fatty acid vinyl esters with more carbon atoms aU; VinyJ-propionate have a higher alkali resistance «il.s V in j.Ln cotal,

2098 18/0830 _BAD

and under the conditions in which they are saponified, the saturated branched fatty acid vinyl esters can also be partially saponified.

it has now been found that the modified polyvinyl alcohols according to the invention has the following general structural formula have, the saturated branched acyl groups remarkably the advantageous ones achievable according to the invention Support effects:

CH ₀ -CH-CH ₀ -CH-CH ₀ -CH-Ch ₀ -CH-

Δ _% Δ , Δ , Δ , OH

O Οίί 0 I. t C = O C = O t I. R ₁ -CK ₀
1, ο CH ₃ H

In the above formula, the sum of the number of carbon atoms in the alkyl groups R 1 to A _{3 is} between 3 and Vom. From the standpoint of water resistance, a sum of δ to 17 is preferable. With regard to water resistance and extrusion properties, the higher the degree of substitution of the saturated branched acyl groups, the better the results are obtained. However, the resistance to organic solvents decreases slightly with an increase in the degree of substitution. A range of 1 to 15 mol is therefore desirable. If the dynamic properties are taken into account, a range of 3 to 9 mol% is preferred. The acyl groups

209818/0830

can be reduced to UuIl by complete saponification, or they can also remain partially unsaponified. In the latter case, with regard to water resistance, it is desirable not to leave more than 15 UoI, ο .icety! Groups, or not more than 30% if particularly high water resistance is required. The modified polyvinyl alcohols according to the invention expediently have a degree of polymerization of JüvJ to 3000, with a range of 50 to 1500 being the most advantageous because a lower degree of polymerization causes a reduction in the strength of the molded body, while a higher degree of ionization reduces the deformability when the The degree of expansion of the saturated branched acyl groups is more than 4 iuene, o, the melt extrusion can be carried out without the addition of a plasticizer at a temperature below the decomposition point, but the addition of a plasticizer such as glycerine, ethylene glycol,! Trimethylolpropane and the like, which are commonly used in polyvinyl alcohols, allow melt extrusion and allow extrusion molding at a lower temperature and improve flexibility. Generally speaking, the greater the amount of plasticizer, the easier it is for the extrusion to be carried out, the greater the number of plasticizers per 100, depending on the water resistance, the dynamic properties of the molded bodies and the compatibility of the modified polyvinyl alcohol with the plasticizer To use parts of the polymer, the lower the amount of plasticizer to be used, the higher the vinyl ester content in the polymer. »/ Uring

2098 18/0830

a. Modified polyvinyl alcohol with a 3ubsütutions- ^ ru-l van less tils u kol-, ϋ in the molten state only swore can be extruded without i '/ oichmachür, tip works a Lriisatv: from ifcar from ο parts of a' ^ ewöhnXlcüen plasticizer i-Hi. JtUiI ■ polyvinyl alcohol, cla) <lieser with one under the 2erf..ei. ^ UnyS] jui »i: t liec-en Teuperatui · the melt extrusion uii" L '.: R-5ogen who can α en the water resistance and the ciynary properties of the! '' ormliörpor and on the precratiiichiieic of the modified i-olyvinyl alcohol

(learning Viuicniäacaor it is desirable that the \ / calibration wheeler in oinei- Kenge from 10 to 4o parts per 10Ü parts modified A-ox / vinylalicohol eiiiäesetEt wirci. JiUJöerdem can in the method NaCN the Liri inaung about iii to about 30 J ₀ of a .. '"Fluids can be added in order to reduce the material costs of the i ^? ormköi'ijcr' ^ iIs such fillers are calcium carbonate, titanoic and carbonate-suitable, but others can also be used.

The invention will now be illustrated by the following examples in f |

individual egg · purifies.

Llußat, -: from G, ύ parts ν,. \ '-Zo-bis-isobutyronitrile (hereinafter referred to as ü ^ L') as -i-polymerization catalyst were <jü, l> parts of vinyl acetate, Ιί, 'Λ Parts of vinyl trimethyl acetate and ib parts of idethanoi "ibv" Hi-nuteii. Polymerized at 100 ° C, -.!. The vinyl acetate was derived from the ex * sustained load from ^ ei, uiiu. the i-asüG wurue in a Liethanolsysteiii box

2 09818/0830

1770A27

an alkali molar ratio of 0.1 and a reaction temperature saponified at 40 C. The saponification product yielded Washing with a modified polyvinyl alcohol using methanol 10.0 mole percent vinyl trimethyl acetate and 1.2 mole percent remaining Acetyl groups. in a yield of 90%. To 100 parts of this modified polyvinyl alcohol, 20 parts of trimethylolpropane was added or diethylene glycol was added and the mixture was at a temperature in the filler section of 150 ° C and a temperature in the compression and metering section deformable from 190 C with an ordinary extruder. The moldings were extremely flexible and insoluble in boiling water and largely non-swellable in high-octane gasoline, benzene, toluene, monomeric styrene, chlorobenzo., Trichlene, perchlorethylene, carbon tetrachloride, Chloroform, dichloroethane and freon.

Example 2

In a polymerization reactor were 89.17 parts of m vinyl acetate, 10.83 parts vinyl-l, l-tetramethylbutancarboxylat 3,3-, 125 parts of water, 0.4 parts of AZN and 0.5 parts of polyvinyl alcohol (degree of saponification 88 mol%, degree of polymerization 2400) and the batch was subjected to suspension polymerization at 60 to 75 ° C. with stirring at a speed of 350 rpm for 360 minutes. The yield of particles thus obtained was 95%. The product was dissolved in methanol, saponified at an alkali molar ratio of 0.08, thereby remaining a modified polyvinyl alcohol having 5 mol% of branched acyl groups and 3.2 mol%

209818/0830. _i4

Acetyl groups was obtained. The differential heat analysis found that this modified polyvinyl alcohol had an endothermic melting point peak at 191.7 ° C which was around 43.2 ° C lower than that of polyvinyl alcohol (234.9 ° C) and which was 7.5 ° C lower than that of modified polyvinyl alcohol with 5 mole percent pelargonyl groups (199.2 ° C). With the addition of 20 parts of diethyl glycol as a plasticizer and 0.5 part of magnesium sulfate as an antioxidant, the mixture deformed in an ordinary extruder, in that in the feed section a temperature of 150 C and a temperature of 190 C prevailed in the compression and metering section. The moldings obtained in this way were sufficiently internally plasticized, they were flexible and opposed very good resistance to organic solvents.

Example 3

In a polymerization reaction vessel, 91.8 parts of vinyl acetate, 8.2 parts of a mixture of vinyl l, l-3,3-tetramethylbutane carboxylate and vinyl 1,2-dimethyl-1-isopropylpropanecarboxylate, 125 parts of water, 0.6 parts of benzene peroxide and 0.03 parts of polyvinyl alcohol (degree of saponification 88 mol%, degree of polymerization 2400) and the batch was stirred for 480 minutes at a speed of 300 rpm 60 to 75 ° C subjected to suspension polymerization. In this way, the yield of particles was 97%. The product was dissolved in toluene and saponified at an equimolar ratio of alkali to vinyl acetate, creating a modified -

- 14 -

209818/0830

V / 70A27

Polyvinyl alcohol with 4.0 mol% branched acyl groups and 0.5 mol% of residual acetyl groups was obtained. The differential heat analysis showed that this modified polyvinyl alcohol showed an endothermic peak at 196 ° C which was about 9 ° C lower than that of modified polyvinyl alcohol with 4 mol% of pelargonyl groups, and it was sufficiently internally plasticized. To 100 parts of this modified one Polyvinyl alcohols were added to 20 parts of trimethylolpropane and the mixture was malleable in an ordinary extruder. The moldings were flexible like those according to Examples 1 and 2 and had good resistance to organic materials Solvent. Table 2 shows the resistance to organic solvents of those obtained according to this example Moldings (the degrees of swelling after 72 hours of treatment at 40 ° C. are given in% by weight).

Example 4

In a polymerization vessel were 83.31 parts of vinyl acetate, 16.7 parts of vinyl versatät (VEOVA 10, manufactured by Shell Oil), 120 parts Y / water, 1.0 part Emalgan (KAO Chemical Co., Ltd.), 0.1 part of sodium lauryl sulfate and 0.3 part Potassium persulfate introduced. The batch was stirred at a speed of 120 rpm for 360 minutes at 60 bis 70 ° C subjected to suspension polymerization. After adding a large amount of salt to the obtained emulsion, it became Polymer salted out, dried, dissolved in methanol and then saponified at an alkali molar ratio of 0.1. It became a modified polyvinyl alcohol with 8 mol% versatyl groups

209818/0830 - 15 -

- is -

and 0.3 MoI-Vo of residual acetyl groups in a yield of 95, o received. This modified polyvinyl alcohol showed an endothermic peak in differential heat analysis 101.7 C, which is the sign that he is consistently internal is plasticized. After adding 0.5 parts of magnesium sulfate This modified polyvinyl alcohol could act as an antioxidant be deformed with an ordinary extruder, the temperature in the filling section 150 ° C and in the compression and metering section was 200 ° C. The on Molded body formed in this way from modified polyvinyl alcohol had good resistance to organic solvents. Table 2 shows the resistance of the moldings to organic solvents.

- 16 -

209818/0830 BATH ORIGINAL

Table 2

Polymer

Modified PVA with saturated branched acyl groups

Modified PVa with saturated straight chain acyl groups

Fully silicone saponified rubber

Composition of the copolymer

Example 3 4 Mol- ¹ / *?

Example 4 8 Mol- ^C -

IO

4 months 1-%

Higher grade

Nitrile

rubber

2098 ' I. Plasticizers Tri-
methylol
propane
20 parts - Trimethylol
propane
20 parts - - - 44 1427 OD Solvent: 0 O
CO n-hexane 0.22S 0.626 0.282 - - - 0 ω
/ - » Isooctane 0.239 0.350 0.815 0.50 132 4th benzene 0.230 0.730 8.81 0.61 130 41, Tetrachlor
carbon 0.390 0.530 21.4 0.55 329 29 Monochlor
benzene 0.310 1.097 14.9 0.81 142 76 Trichlene 0.401 3.47 22.3 - - - Note: weight gain (%) after 72 hours of immersion at 40 ° C

- IV -

As can be seen from table 2, the modified polyvinyl alcohols with saturated branched acy groups are considerably better resistant to organic solvents than commercial rubber and modified polyvinyl alcohols with saturated straight-chain acyl groups, and it was found that modified polyvinyl alcohols with 4 to 8 Uol -% saturated branched acyl groups have almost the same resistance to organic solvents as common polyvinyl alcohols.

Claim i

209818/0830

Claims (1)

Claim Process for the production of modified polyvinyl alcohol bodies, characterized by dai ^ a Kopoiymerisat of vinyl acetate and one or more saturated branched ones Fatty acid vinyl esters of the general formula CH ₀ -CHOCOCR ₁ tt _o it. in which R ₁ to R, are alkyl groups, is saponified to obtain a modified polyvinyl alcohol and that the modified polyvinyl alcohol thus obtained is extruded in the presence or absence of a plasticizer in the melt or semi-melt process. 209818/0830