CS254335B2 - Phenol-stabilized polyvinyl butyral foil - Google Patents

Abstract

Es wird vorgeschlagen, in Verbund-Sicherheitsgläsern mit Zwischenlagen aus Polyvinylbutyral-Folien mit Gehalten von phenolischen Stabilisatoren und Gehalten von Phosphorsäuretriestern bzw. Phosphonigsäurediestern, zusätzlich UV-Absorber zur Behebung der Vergilbung bei langer Gebrauchsdauer zuzusetzen.

Description

The present invention relates to plasticizers containing partially acetylated polyvinyl vinyl alcohol-containing foils, which are used as adhesive films in laminated safety glasses. ·

Laminated safety glasses generally consist of two silicate glass panes and one adhesive film connecting the glass panes. Alternatively, one silicate glass sheet may also be replaced by a synthetic glass sheet. Such safety panels are mainly used as vehicle windscreens; however, they can also be used in the construction industry, whereby more than two silicate or synthetic sheets can be joined by adhesive foils, depending on their purpose. Such multiple laminated panes serve, for example, as armored laminated panes. Laminated safety glasses are produced by compressing ifolias and glass panes at pressures of 0, 5 to 2.0 MPa and 125 to 155 ° C or very preferably in autoclaves.

Plasticized, partially acetalized polyvinyl alcohol films serve as adhesive films in laminated glasses. The partially acetalized ipolyvinyl alcohols necessary for their production are produced by saponification of polyvinyl acetate and subsequent acetylation with C 3 -C 10 alkali aldehydes, such as in particular formaldehyde, acetaldehyde, butyraldehyde. The saponification is generally not carried out perfectly, so that polyvinyl alcohols most often still contain 0.5 to 5% by weight of acetyl groups, calculated as vinyl acetate groups. Also, the acetalization is not generally carried out perfectly, so that the partially acetalized polyvinyl alcohol used for the production of films most often still contains free OH groups; in the case of a partially butyralized vinyl alcohol (PVB) pole, this hydroxyl group content may be 10 to 27% by weight, calculated as vinyl alcohol.

In the manufacture of composite safety glasses, these partially acetalized polyvinyl alcohols with a certain plasticizer content are used as films. The type and amount of plasticizer used affect the properties of the safety glass. In practice, it has been found that a safety glass particularly resistant to shattering is to have a PVB foil as an intermediate film which has a plasticizer content of 15 to 40% by weight, preferably 25 to 31% by weight, and whose free OH group content is based on 10 to 25% by weight, preferably 16 to 23% by weight, of a plasticizer-free PVB resin; The moisture content of such a PVB film should be between 0.2 and 0.9% by weight.

More particularly, the invention relates to films of plasticized, partially acetalized polyvinyl alcohol with good oxidation and temperature resistance and excellent light resistance. The plasticizer-containing polyvinylbutyral is exposed to high temperatures, which, to some extent, lead to yellowing under the conditions of its film-forming and subsequent processing into laminated glass. In particular, the optical properties are deteriorated.

It is known that phenolic compounds such as 2,6-di-tert-butyl-p-cresol, 2,4,6-trimethylphenol, octylphenol, bornylxylenol and others are known to stabilize the mass (DE-A-2 208 167). . Furthermore, it is known that phosphorous acid triesters such as tnilauryl phosphite, decylphenyl phosphite and γ are used to prevent yellowing. (DE-A-2 208 167).

In contrast to softened polywinylchloride PVC formulations, in which the addition of phosphorous acid phosphorous stabilizers as a color enhancer, transparency and light resistance, however, it has been shown that PVB films containing phosphorous acid triester are lost after prolonged periods of illumination. their original light color and not to a significant extent turn yellow. In particular, in the case of safety waterproof glass films, previously desired by the consumer, it was an object of the present invention to find a way to improve the light-resistance time and to prevent it during the time of increasing yellowing.

Yellowing due to long-term illumination has been observed using a number of phosphorous acid triesters or phosphonous diesters such as decyldiphenyl phosphite, trilauryl phosphite, didecylphenyl phosphite, tris-nonylphenyl phosphite, triphenyl phosphite, di- (isodecyl) -pentaerythritol diphosphite, titheryl diphosphite, di-stearate diphosphite, 4-di-tert-butylphenyl 1 -4,4'-di-phenylylene diphosphite.

It has therefore been assigned the task of stabilizing polyvinyl butyral films, i.e. PVB films in laminated safety glass, containing the phenolocol compounds and stabilizers ла based on phosphorous acid esters and / or diesters of phosphonic acid, by additional measures against the influence of daylight. aging with a significant long-term effect against yellowing.

Surprisingly, it has now been found that the long-term effect of preventing the yellowing of phosphite-containing film formulations is achieved by the addition of selected UV absorbers and, even under long-term exposure to light, yellowing due to the necessary addition of phosphites or phosphonites is prevented.

SUMMARY OF THE INVENTION The present invention provides a phenol stabilized polyvinyl butyral film comprising a plasticizer comprising a phosphorous acid triester and / or a phosphonic acid diester and from 0.01 to 0.40% by weight of at least one UV absorber selected from the group consisting of benztriazoles, acrylonitrile derivatives, cinnamon nitrile derivatives and hydroxybenzophenone derivatives.

Selected UV absorbers provide very good protection against aging and have a long-lasting effect against yellowing. Other groups of conventional UV absorbers, on the other hand, do not.

For example, phenylsalicylates and derivatives thereof such as phenylsalicylate, 4-tert-butylphenylsalicylate or 4-octylphenylsalicylate as well as spherically hindered amines acting as light protective agents such as bis-2,2,6,6-tetramethyl- The 4-piperidyl sebacic acid ester does not provide the long term effect and exhibits too high specific values of E and possibly YI in the long term experiment.

Suitable UV absorbers are those which, inter alia, can be assigned to the following substance classes:

1. Benzotriazole derivatives, in particular hydroxyphenylbenzotriazole, such as:

2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2'- (2-hydroxy-3 ^<, 5'-di-tert-butylphenyl) -5-chlorotriazole, ^from? - (2 &apos; -hydroxy -3 ', 5 ^£ di-tert-butylphenyl) benzotriazole, 2- [2-hydroxy-3 ^{£ £} -t-butyl-5-methylphenyl-5-chlorbenztriazol, 2- (2 ^<-hydroxy-3 _'l 5'-di-tert-amylphenyl) benzotriazole,

2- (2 ^£ hydroxy-5'-tert-o'ktyl6enyl) benzotriazole.

2. Acrylonitrile derivatives, for example cinnamic acid nitrile, for example α-cyano-4-diphenylacrylic acid ethyl ester, α-cyano- [3-methyl-4-methoxycinnamic acid methyl ester.

3. Hydroxybenzophenones such as: 2,2‘-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxy'benzophenone, 2-hydroxy-5-chlorobenzophenone, 2,2 ‘, 4,4‘-tetrahydroxybenzophenone.

It is also possible to use mixtures of these UV absorbers from the same or different groups of substances.

Preference is given to using UV absorbers which have no or no tint of their own coloring, or those which do not cause any coloring of the foil mass, for example 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole or ethyl ester, and cyano -? - diphenylacrylic acid.

Examples The 0.8 mm thick PVB film for the production of vehicle glass panes was supplemented with 30% based on a 70% by weight base formulation of partially butyral polyvinyl alcohol containing 20% by weight of polyvinyl alcohol. % of 2-ethylbutyric acid triethylene glycol ester as plasticizer; and 0.3% by weight of bornylxylenol as phenolic stabilizer; and in Comparative Examples 2 to 6 with phosphite or phosphonite as additive, and then processed to films.

Comparative Examples 1 to 6

The following stabilizers have been added to the basic PVB film recipe:

a = decyldiphenyl phosphite b == tris (2,4-di-tert-butylphenyl) phosphite c = trisnonylphenyl phosphite d = di-stearyl-pentaerythritol diphosphite e = tetrakis (2,4-di-tert-butylphenyl) -4,4 ' -bisphenylylenediphosphonite by weight, additives total color deviation ΔΕ yellowing index po versus standard po

1 week 10 weeks 20 weeks 1 week 10 weeks 20 th week

1 none 0.73 0.31 1.79 1.17 1.76 2.79 2 0,1a 0.81 1.84 4.52 0.72 2.76 4.73 3 0.1 p 0.91 1.06 3.53 0.99 2.57 4.20 4 0,1c 0.77 1.72 4.44 0.90 2.77 4.62 5 0,1 d 1.07 1.58 4.22 0.77 2.40 4.37 6 0,1 e 0.67 1.08 3.24 0.90 2.14 3.69

Addition of phosphites or phosphonites in the long-term experiment leads to increased dye values, which can also be evaluated as a yellowish color by the naked eye.

According to Comparative Examples 2 to 6, 2- (2‘-hydroxy-5‘-methylphenyl) benzotriazole (m) was additionally added as UV absorber according to the invention.

Examples 7 to 11

Into the basic recipe of PVB foil, with aditi254335 wt. % by weight, total color deviation of the UV additive AE against the standard after the yellowing index after

beru m 1st week 10 th week 20 th week 1st week 10 th week 20.týd. 7 0,1a 0.1 0.66 0.45 0.84 0.89 1.09 1.24 8 0.1b 0.1 0.63 0.91 0.86 1.49 1.35 1.32 1.09 9 0,1c 0Д 1.04 0.82 0.95 1.57 1.65 10 0,1 d 0.1 0.63 0.60 0.53 0.56 0.94 1,22 1.35 11 0,1 e 0.1 0.72 0.98 1,16 ' 1.09 1.14

The measured values of the long-term experiment show considerably less color values than the corresponding comparative examples 2 to 6.

There is practically no yellowish discoloration with the naked eye.

It is often sufficient to confine itself to simply admixing the UV-absonbers in an amount of 0.1 to 0.2% by weight. In general, an amount of 0.01 to 0.40% by weight, preferably 0.03 to 0.30% by weight, is used.

The long-term effect of the added UV absorbers was measured in lighting experiments on laminated glass consisting of 0.8 mm PVB-film placed between two 2.8 mm thick glass panes, in a rotary solarium according to German utility model No. 7819 931 at intervals of 1 up to a total of 20 weeks. For evaluation, the total color deviation AE according to DIN 6 174 or the yellowing index (YI) according to ASTM-D-1925 is determined.

In the following examples, for the sake of comparability, the same basic recipe of the PVB film and the above-mentioned laminated glass thickness are selected, but the reduction of the measured values of the same kind is achieved with other PVB recipes by the UV absorbers of the invention.

Examples 12 to 14

The following UV absorbers according to the invention were additionally added to the basic recipe of the PVB film with the additive according to Comparative Example 2:

n = 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole o = 2-hydroxy-4-n-octyloxybenzophenone p = ethyl a-cyano- (S, 3) ethyl ester % diphenylacrylic acid wt. % w / w, total color deviation of AE of the additive UV-absorber compared to the standard after the yellowing index after tin 1 week 10 weeks. 20 th week 1st week 10th week 20 th week

12 0,1 a 0,1 n 0.69 1.04 2.59 1.06 1.87 3.29 13 0,1a 0, lo 1.01 0.59 0.63 0.78 1.14 1.56 14 9.1a 0.1 p 0.90 0.86 2.36 0.94 1.82 2.80

The long-term experimental data for the UV absorber n from the group of benzotriazoles, □ from the group of benzophenones and β from the group of cyanoacrylates also show lower readings compared to Comparative Example 2 and a very slight yellowish color when observed with the naked eye.

The compound Q from the group of salicylates and г from the group of piperidyl esters of carboxylic acids, but these fail.

Q = phenyl salicylate r = bis-2,2,6,6-tetramethyl-4-piperidyl sebacic acid ester

Examples 15 and 16

In accordance with the foregoing examples, masses were washed. % by weight, total color deviation AE of the UV-ab-standard additive to the yellowing index after

sorberu 1st week 10 th week 20 th week 1st week 10 th week 20 th week 15 Dec 0,1a 0.1 Q 0.69 4.05 6.94 1.08 4.96 7.03 16 0,1a 0,1 y 0.42 1.38 3.56 1.33 3.04 5.42

The results of the long-term experiments show the usability of the substances Q and r, while the shortcomings in the experiment do not reveal the drawbacks. The eye shows a yellow color after a long-term experiment.

Examples 17 to 34

UV absorbers m, o and p are added to the base additive formulation of Comparative Example 2 in the amounts listed below.

% wt. % by weight, the total color deviation of the UV-ab- additive against the standard after the yellowing index after

soňbéru 1st week 10 th week 20 th week 1st week 10.týd. 20. week, 17 0,1a 0.01 m 0.77 2.27 5.34 0.89 3.16 5.63 18 0,1a 0,03 m 0.73 1.44 4.50 0.88 2.65 4.91 19 Dec 0,1a 0,05 m 0.96 0.56 2.35 0.85 1.69 3.25 20 May 0,1a 0,07 m 0.66 0.50 2.02 0.84 1.41 2.74 21 0,1a 0,10 m 0.66 0.45 0.84 0.89 1.09 1.24 22nd 0,1 a 0.20 m 1.29 0.97 0.86 1.18 1.04 0.87 23 0,1a 0.01 o 0.58 1.36 4.89 0.68 2.06 4.96 24 0,1a 0,03 o 0.66 0.74 3.42 0.86 1.42 3.32 25 0,1a 0,05 o 0.90 0.56 2.66 0.90 1.39 3.05 20 May 0,1a 0,07 o 1Д4 0.53 1.55 0.88 1,28 2.39 27 Mar: 0,1a 0,10 o 1.01 0.59 0.63 0.78 1.14 1.56 28 0,1 a 0,20 o 1.09 0.60 0.60 0.96 1,22 1.38 29 0,1 a 0.01 p 0.75 0.84 4.51 1.40 1.90 4.47 30 0,1a 0,03 p 0.91 1.65 6.70 0.81 2.90 6.74 31 0,1a 0.05 p 0.61 1.03 4.92 1.03 2.32 5.08 32 0,1a 0,07 p 0.65 1.14 3.66 0.97 2.18 3.83 33 0,1a 0,10 p 0.90 0.86 2.36 0.94 1.82 2.80 34 0,1a 0.20 ip 0.55 0.55 1.64 1.16 2.15 2.53

In the long-term experiment, the amounts added are from 0.01 to 0.03. % by weight, noticeable improvements in color values. Amounts of additives of between 0.1 and 0.2% by weight, cause very low color values, required by special requirements or, in particular, for long-term use.

Claims (1)

SUBJECT A phenol-stabilized polyvinyl butyral film comprising a plasticizer, characterized in that it comprises phosphorous acid triester and / or phosphonic acid diester and from 0.01 to 0.40% by weight of at least one UV VYNALEZU an absorber selected from the group consisting of benztriazoles, acrylonitrile derivatives, cinnamon nitrile derivatives and hydroxybenzophenone derivatives.