DE1720441C - Process for the production of modified oxymethylene copolymers - Google Patents

Description

a pH value between 9 and 13 carried out. z ₅ s at and those

Numerous oxymethylene copolymers are already known in which other groups, which form links in the chains, are distributed along the chains of oxymethylene groups of which the polymer molecules largely consist. With a certain type of copolymer, these contain other groups or ~ ^: ~ ^: - "" · ** iVinon ϊ <* pin carbon atom that does not

et

Voretufcncopoi ^ _{t wefden} vor

^s ^ ^e ' ^a " ^S ^ for example by spraying and

_η Χ _{ε50ηαεΓε clearly} superior in terms of the improved J clarity and S! * certain applications have considerable advantages

Copolymers which are hereinafter referred to as copolymers with lateral haloalkyl radicals raw materials are door according to the V «years of the invention for the production of modified oxymethylene copolymers.

A process for making modified polyoxymethylenes from at least one halogen atom containing homo- and copolymers ^ of formaldehyde or trioxane is already known from the German Auslegeschrift 1233 600. There the Reaction with ammonia, amines or hydrazine and leads to nitrogen-containing ionic polyoxymethylenes. .

In contrast, the invention is a Process for the production of modified oxymethylene copolymers, the resulting

and can be prepared by copolymers with epichlorohydrin or with ll ^ -dioxolane. Weij ^ Ve copolymers are _unte similarly L f _{ers eLLB} a _r r use of homologues of herste mai ^ to _{defe such that up to} four

^ J ^ J ^ _between the chloromethyl and ^ h ^ group, _{and isoraere} n of 4-chloro

ν ^ \ _ΏΤ οχο1αη, for example 4-chloromethyl ^^^^ J e.chlormethyl-S ^ ^ -dioxola Also 2fi o ^"u _bromsu bstituierten compounds which _n ^s J ^sp _{n; be e r} ^{e c} ^ _{friend D} ie. Vorstufencopolymeri- _ _{ate could} n addition sate other groups "> oxyethylene groups and / or groups

™ ^ _onome / _en , _{such as} p _e ntaerythntdiformal Vinyl- ^ X ^ i ^ .yd _or Butanedioldiglycdylather,

^ab Dttrb; nL _g en, mitdenend _a sPre-stage copoly;

SS% nSeT «Ä« radical - SMe and at least one radical - COOMe, in which Me denotes mono- or polyvalent metal atoms, in at least the halogen atoms of the oxymethylene copolymer equivalent amounts

implements. . , _ _nIu

The hergesteluen by this process copolymers are superior to the previously known of ι * g jhioigruppe and the carboxyl "^ _M ^ of both _{de-icing salts vorlie} g _s. Suitable

gJ ^^ _of homologs, for example of ^s _D ⁿ _m Xi _thiog , _yko oleic acid, and salts of Verbm _d which contain several carboxyl groups, of

^ _E ine _least one Metallsatees wenigsi in the form

is present, for example salts of the compounds

HS-CH-COOH

COOH
HS-CH-CH ₂ -COOH

COOH

HS-C (CH ₃ ) -CH ₂ -COOH

COOH
HS-CH-COOH

CH ₂ - COOH

. · '.- salts are those of monovalent or mc! . few metals, however, salts of Aik.t: .- or alkaline earth metals including magnesium preferred. The alk. 1; salts are particularly preferred.

A reaction between the compound containing the thiol group and the precursor copolymer takes place between the metal atoms bonded to the thiol sulfur atoms and the halogen atoms in the haloalkyl side groups in the precursor polymer with the formation of metal halides. In this regard, worshiping according to the invention is completely different from coupling a thiol with an ethylenically unfoamed polymer, which is a free radical reaction carried out under conditions which inevitably result in vigorous oxymethylene copolymer runoff. The reaction is preferably carried out using an excess of the compound containing the thiol group over the amount equivalent to the halogen in the haloalkyl side groups in the precursor copolymer. An excess of 100% is preferably used, but a larger excess of up to 1000%, for example, can also be used. The reaction is preferably carried out in an aqueous solution of a lower alkanol, for example in aqueous methanol, as the reaction medium and at a pH between 9 and 13, in particular between 10 and 12. The reaction can be carried out in an autoclave, the reaction mixture being ^{heated rapidly to a temperature of, for example, 120 to 180 °} C., preferably at a temperature in the vicinity of 160 ^° C. At this temperature the resulting pressure can be 14 to 16.8 atmospheres. The time required to reach the desired reaction temperature varies depending on factors such as the heating device and the size of the reaction vessel, and it can be 10 minutes to 2 hours or more. When the reaction temperature is reached, it is maintained until the reaction has progressed to the desired level, for example 0.25 to 6 hours, preferably 0.5 to 4 hours. The product can be obtained by pouring the contents of the reaction vessel into deionized Water is discharged, the pH of which has been adjusted to at least 10. This is how the ionic

Copolymer precipitated as a strongly swollen gel, which is separated off by filtration or centrifugation and Washed salt-free with water, a lower alcohol or aqueous alcohol and finally with Acetone can be washed to speed drying with the help of air at room temperature for 12 to 20 hours.

In addition to the advantageous properties already mentioned, modified copolymers are according to the invention also remarkable in other respects. It has been found that the adhesive strength of coatings on films or others Objects made from the ionic copolymers is much better than corresponding Products which, however, are made from the precursor copolymers. This can be illustrated by coating foils with paint, letting the paint dry, clean them with a sharp knife hatched, pressure-sensitive adhesive strips onto the painted surfaces and then peeled off the adhesive strips. In this test, the color film remains in the case of the films made from the copolymers produced according to the invention completely or almost completely obtained, while the films from the precursor copolymers To lose all or almost all of the paint. The modified ionic copolymers are therefore special Value in film form or in the form of a laminate with a flat material other than with Labeling of packaging material. It is true that these ionic copolymers burn, they form however, in doing so, a non-dripping charred mass that comes into contact with a cold surface can be easily deleted. In contrast to this, in the case of the precursor copolymers form during of burning puddles of molten polymer that continue to burn. The compilation of Flame retardant masses with the help of flame retardants is therefore with the ionic copolymers lighter.

The modified copolymers prepared according to the invention can be thermally processed in the usual way stabilize by using stabilizers, such as nitrogenous Nuclear fission inhibitors such as cyanguanidine alone or in combination with melamine, the same type as used for thermal stabilization of nonionic oxymethylene copolymers are used, can be added. Furthermore can UV stabilizers, fillers such as glass, metal or cellulose-containing materials are also used in the usual way Materials in fiber form or other form, plasticizers, pigments and dyes are added.

In the following examples which illustrate the invention, ionic copolymers were prepared from a number of different precursor copolymers which were prepared using different comonomers and varied by the type and proportions of the comonomer and the polymerization conditions. Epichlorohydrin (CEP), pentaerythritol diformal (PEDF), vinylcyclohexanediepoxide (VCH) and butanediol diglycidyl ether (BDGE) were used as comonomers in the proportions of the monomer mixture given in Table 1 (remainder trioxane). The intrinsic viscosities IV of the polymers were at 6O ⁰ C in a solution of p-chlorophenol / a-pinene: determines a concentration (C) of 0.1% (98 2). Previously, the polymers were in a known manner by heating in a 2- to 5% solution of triethylamine in aqueous Me-

THANOL (methanol concentration 55 weight percent) to 160 ⁰ C at a pressure from 14 to 16.8 atm stabilized, then precipitated into cold water, washed with acetone and dried.

Table 1
Precursor copolymers of Examples 1 to 12

Proportion of comonomer Others I.V. Comono- at
spat] CEP mergroups
Per
100 CH ₂ O- 10 - 0.82 groups 1 14th - 0.39 3.2 2 15th - 0.74 5.0 3 21 - 0.38 4.6 4th 5 - 0.92 6.7 5 30th not 1.6 6th 2 PEDF definitely 9.1 15th 0.5 VCH 0.57 7th 15th 0.3 BDGE 0.68 5.25 8th 15th 2 BDGE 0.53 4.7 9 15th not 5.8 10 definitely 5.2

Comonomer groups

Per
100 CH, O-

Gmppeii

Disodium thioglycolate (DSTG) was in solution in aqueous methanol (55 percent by weight methanol) by neutralization of thioglycolic acid in

• 15 aqueous methanol with flaky (or 50% aqueous) sodium hydroxide and the solution adjusted to pH 10 to 12. Per 100 parts by weight of thioglycolic acid were 88 parts by weight of sodium hydroxide for the preparation of the di-

hatrium salt required. The precursor copolymer was added to the solution and the mixture was heated in an autoclave to about 160 ° C (14 to 16.8 atü) and held at this temperature for 1 hour. There* modified copolymer was in water, with

Sodium hydroxide brought to pH 10, precipitated. washed three times with methanol and then once with acetone and finally dried. The conditions the treatment are given in Table 2 below.

table

example Aqueous methanol Prepress
copolymer DSTG DSTG
Mole / mole Cl yield S. 1 G G G % 1 3.5 400 370 7.0 420 2.5 2 18th . 1000 025 4.66 944 4.3 3 20th 415 415 2.31 816 3.5 4th 18th 1000 925 3.36 1004 4.3 5 20th 1000 148 2.27 1215 1.3 6th 18th 1050 925 2.74 1369 6.1 7th 18th 1000 925 • 4.57 1192 3.5 8th 18th 1000 925 5.03 1478 3.5 9 18th 1000 925 4.17 not determined 4.3 10 18th 1000 415 2.04 827 3.9 11th . 18th 1000 415 2.40 980 3.5 12th 18th 1000 925 3.40 1097 5.2

As already mentioned, one of the outstanding properties of the ionic copolymers prepared according to the invention is their clarity, which can best be determined on films according to ASTM method D 1003-61, in which the scattered light transmittance and the total transmittance are measured and the "haze", ie Sire light transmission divided by total transmission is determined. The films that had μ a thickness of 178 ± 50 were subjected from the dried under reduced pressure for 2 hours at 110 ⁰ C copolymer between metallized polyester films which were deposited with iron sheet, at 18O ⁰ C 30 seconds pre-heating without pressure and at Pressing time of 60 seconds under a pressure of 201 pressed. The films had a size of 12.7 cm ² . A difference in clarity resulted depending on whether the film was cooled quickly or slowly. Typical results are given in Table 3 below. In this table means! "Quickly cooled" means that the mold was quickly transferred to a water-cooled press at around 16 ° C after pressing. "Slowly cooled" _be: indicates that the form gebfacht in a press at 90 ⁰ C and there for 3 minutes kept under pressure before removed from the press and the cooling was left at about 25 ° C. For comparison, the permeability and opacity numbers of two precursor copolymers are given.

example table 3 Slow chilled 100 5 Fast ! ccool Through
nonchalance Cloudiness
5 Polymer ' 1 Through
nonchalance Cloudiness 93 Prepress 74 99 Prepress 5 83 98 IO 76 15 Ionic 83 Polymer 1 82 98 89 Ionic 72 Polymer 11th 77 77 29
20th Ionic 64 Polymer 3 68 40 27 Ionic 67 Polymer 9 72 28 7th Ionic 73 Polymer 12th 82 8th Ionic 74 Polymer 6th 77 17th Ionic 85 Polymer 87 8th

25th

Is the percentage turbidity as a function of the thioglycolate content in moles / 100 Ch ₂ O groups for both the slowly cooled and the rapidly cooled pressed films made of ionic binary polymers of trioxane and epichlorohydrin and ternary polymers of trioxane, epichlorohydrin and butanediol diglycidyl ether in the form of curves shown, it is found that the presence of only a few ionic groups has a relatively small effect, but that at about 3 or 4 moles per 100 CH ₂ O groups, the percentage turbidity quickly decreases. Optimal transparency of the films is only achieved with approximately 6 to 8 mol of ionic groups per 100 CH ₂ O groups. The slowly cooled films are all considerably less transparent than the rapidly cooled films with the exception of the films with the highest content of thioglycolate groups. It is interesting to note that slowly cooled films made from the ionic copolymers show significantly larger crystallites in the X-ray analysis than films made from the precursor polymers.

The melting points of the ionic copolymers usually do not differ greatly from those of the corresponding precursor polymers, although they are sometimes somewhat lower. The quick chilled ones Films made from ionic copolymers, however, have a noticeably higher ductility than films made from the corresponding precursor polymers. For example, the films made from ionic copolymers of Examples 1 and 5, which were stretched at a speed of 5 mm / minute, Elongations at break of 31 and 20% determined compared to 10 and 17% for films made from the precursor polymers.

An important difference between the copolymers prepared according to the invention and their precursor polymers lies in their flow properties under pressure, as shown by their melt indices determined in accordance with ASTM D-1238. In general, an ionic copolymer has a significantly lower melt index than its precursor polymer. Furthermore, the temperature dependence of the melt viscosity is greater in the case of the ionic copolymers than in the case of the corresponding precursor polymers. This is illustrated, for example, by the fact that a temperature increase of 20 ^° C. in the products of Examples 1 and 5 causes a greater increase in the melt index than a temperature increase of 40 ^° C. in the case of commercial nonionic copolymers otherwise of the same constitution. Examples of the melt index counters determined are given in Table 4 below.

Table 4
Flow properties of ionic copolymers

Intrinsic viscosity

190 "C melt index (decigrams / min.)

lOX melt index (decigrams / min.)

Ratio of 10X / 1X

170 ⁰ C melt index (decigrams / min.)

lOX melt index (decigrams / min.)

Ratio of 10X / 1X

Ratio melt index 190 ° C / melt index 170 ⁰ C

It is also possible to use the metal atoms in the copolymers prepared according to the invention to be replaced by other metal atoms by ion exchange from solutions of, for example, metal chlorides)

example It 5 1 1.5 0.7 0.6 0.13
4.7
36 5.5
130
24 1.4
32
• 23 2.2 0.44
10.4
24 2.5 3.2

209651/4

Claims (2)

1 Process for the production of modified 5 oxymethylene copolymers, marked thereby ^ aßmanin better known wise oxymethylene copolymers, the Ibis40 haloalkyl side radicals contain per 100 oxymethylene residues, with saturated aliphatic connec- .o fertilize, which have a remainder - SMe and at least one remainder -COOMe, in which Me mean monovalent or polyvalent metal atoms, in SLd at least the halogen atoms of the oxymethylene ^ polymerizate converts equivalent amounts. 2. The method according to claim 1, characterized in that the one radical - SMe and at least one radical - COOMe having ^. _{the position} gJ _h casting or molding under thin ™ £ _{S sintL} ie are attributed pressure ™ NSS _ste i _ge ndem halogen content in the output product the crystal order ^^ ynSat is lower, whereby hencop y _{z verbe} ^ ert, Harte and . ^D £ f ^ rTringer be. It is believed to be figtat but ger g ^^ g ^ u from the ^ SSgkeit consists of the melt, _formed polymerizat ionic forces the crystallization _{size of} the crystallites reduced the neutralizing Kaüo-