DE2410153A1 - PROCESS FOR MANUFACTURING MODIFIED, SEMI-ACETALIZED POLYVINYL ALCOHOL FILMS - Google Patents

Description

Troisdorf, March 1, 1974 OZ: 74 023 (2319)

DBTAMIT UOBEL AKTIENGESELLSCHAFT Troisdorf, owner Cologne

Process for the production of modified, partially acetalized vinyl alcohol film

They are composite panes "" consisting of two or more panes of glass and an adhesive film connecting the glass panes, for example made from a partially acetalized polyvinyl alcohol.

It is also known as an adhesive film in making toc Glass / plastic terbund disks made of plasticized polyvinyl butyral (PVB). Suitable plastic washers are in particular those made from amorphous polyamides (cf. DBP 1 596 781).

For the production of yerbunus safety slices where a particularly splinter-proof network for safety reasons is required, v / calibrated, partially butyralized polyvinyl alcohol films have proven their worth Moisture content from 0.2 to 0.9 wt .- ^, free OH groups (calculated as vinyl alcohol) from about 10 to about 25, preferably from approx. 16 to approx. 23 wt from approx. 18 to approx. 65 parts by weight, preferably 35 to 4-4

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Parts by weight per 100 parts by weight of PYB,

Laminated safety panes, "consisting of two panes of glass
and an adhesive film, preferably made of PVB, which connects the glass panes, is used in particular as windshields in motor vehicles
Glass pane through a plastic pane, mainly made of
an amorphous polyamide, can be replaced. Such silicate glass / silicate glass or silicate glass / plastic composites are also used in the construction sector, for example as window panes or as partition walls, and depending on their use, e.g. Layers exist, are used.

The partially acetalized polyvinyl alcohols are produced by saponifying polyvinyl acetate and then acetalizing with aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and the like. They contain
usually about 0.5 to 5 wt .- #, usually about 0.5 to 1.2 wt .- 5 acetyl groups, calculated as vinyl acetate residues. Others too
Polyvinyl esters of aliphatic acids with up to 9 carbon atoms can be saponified and then acetalized.

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The partially acetalized polyvinyl alcohol resins, in the following PVA resins are called, along with plasticizers, if appropriate Stabilizers and, if necessary, other additives processed into films in devices known for film production, e.g. on extruders. To set the for Yerbund safety glasses with the required moisture content will be used if necessary ' post-treated in a climatic chamber.

In practice, composite safety panes are usually produced in such a way that the load-bearing single layers and the adhesive film are first brought into a pre-bond at an elevated temperature, with the laminate being expediently vented. Thereafter, this preassembly is brought into the final bonding under temperature and pressure, for example in an autoclave _y eg at pressures of about 10 to 15 kgf / cm and at temperatures between about 130 to 150 ⁰ C.

The thickness of each layer of laminated safety glass can be varied as required, depending on the intended use. The following layer thicknesses have proven effective for windshields in vehicle construction: Glass = 1 to 3 mm, preferably 2 mm / PVB = approx. 0.30 to 0.80, preferably 0.76 mm / glass 2 to 4 »preferably 3 mm.

Esters of polybasic acids or polyhydric alcohols, e.g. dibutyl sebacate, di- (jB-butoxyethyl) adipate, are suitable as plasticizers. Dioctyl phthalate, triethylene glycol

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2A10153

bis-diethyl acetate, triethylene glycol di (2-ethyl butyrate) and like that.

In the case of laminated safety windows that are used as windshields in Motor vehicles are used, the adhesion of the glass to the film must be optimal. Palis namely through the disc If the impact is destroyed, a breakdown occurs in the center of the impact with very high adhesion, without a lot of glass splintering. If the adhesion is very poor, the impact tool, e.g. a hammer or a falling body, will be elastically intercepted by the film, however, the splintering effect is very great. In the event of a rear-end collision with destruction of the window due to the impact of the On the one hand, the film should slowly reduce the kinetic energy through stretching, on the other hand, the destroyed No matter how well the glass adheres to the film, dangerous cuts are avoided. For this reason, the adhesive force must be optimally adjusted.

When used as building glass, e.g. as a window pane, on the other hand, a high adhesive force of the glass on the film is desirable, because the main aim here is to eliminate cuts.

The problem with the adhesion of a pane of glass to a partially acetalized one Getting PVA under control is critical to the windshield sector.

It is known that plasticized, partially sutyralized PVA films generally have a very high level of adhesion to the glass

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but is undesirable for the windshield sector. Desirable are pummel values of 2 to 4 for windshields in automotive engineering

A number of publications are known from the literature which deal with the problem of the manufacture of windshields deal for motor vehicles and in which it is proposed to lower the adhesive force by adding salts to achieve organic acids.

However, these known procedures have the disadvantage that a number of salts can cause discoloration of the film. In addition, with such additives there is a risk that there will be delamination phenomena the film comes from the glass surface, as the salts are sensitive to moisture and thus the moisture content adversely affect the adhesive film. In addition, these agents only have an effect that reduces the adhesive force demonstrate.

It is also known that can be influenced to an inorganic substrate having bestimmmten compounds siliciumorganiscben _s DJE adhesion of a synthetic resin. Such compounds are the silanes. The silanes are substitution products of silicon hydrogen. The substituents can be of different characters. According to Noil, Chemie und Technik der Silikone, 2nd edition, 1968, page 10, the silanes are divided into the groups "only silicon-functional", "only organofunctional" and "silicon and organofunctional". In the case of silicon-functional silanes, the functional groups, such as halogens or alkoxy groups, are linked directly to the Si atom. Such groups are easily hydrousable. The organofunctional

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- 6 groups are bonded to silicon via one or more carbon atoms, and they are reactive, e.g. due to amino or epoxy groups or due to double bonds. These introduced by HoIl Nomenclature is also used in the following.

From US Pat. No. 3,341,399 it is known to join glass plates together using a PVB film treated with a silane associate. Both silicon-functional and silicon- and organofunctional are proposed as silanes, namely Aminoalkyl-triethoxysilane, alkyltriethoxysilane, aryltriethoxysilane and yinyltriethoxysilane. They will be in quantities of the PVB 1 to 10 wt .- ^ added. This procedure was based on the task both shear strength and steam resistance to increase the network. Adjustment of the adhesive force of partially acetalized PVA-oils containing plasticizers on inorganic ones The US patent does not seek to achieve the pummel values required for the particular application. Nothing could be extracted from this US patent specification to solve the problem on which the present invention was based v / earth.

The invention relates to a method for adjusting the adhesive force of partially acetalized polyvinyl alcohol films containing softener on inorganic glasses to the pummel values required for the respective application, which is characterized in that the partially acetalized polyvinyl alcohol resin either before or during processing into a film by processes known per se, predetermined amounts

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a) a silicon-functional silane which reduces the strength
or a mixture of different silicon functional
Silanes or

b) a silicon-organofunctional silane which increases the adhesive force or a mixture of silicon-organofunctional ones
Silanes or

c) a mixture of at least one silicon-functional
Silane with at least one organofunctional silicon
Silane adds.

The invention also relates to laminated safety disks which have been produced using partially acetalized polyvinyl alcohol-IP films which have been modified in this way.
According to the invention, the silicon-functional silanes are preferably those of the general formula

^E n - ^S1 - ^E 4 - η

inserted, in the R the same or different, saturated, straight or branched alkyl radicals having 1 to 18 carbon atoms, R halogen, preferably Cl, or identical or different saturated ones Alkoxy groups with 1 to 8 carbon atoms, optionally through

Heteroatoms, such as -0- or -S- are interrupted, mean and η is 0 to 3.

Examples include: propyl-triethoxysilane, propyltrimethoxysilane, isopropyl-dimethoxy-ethoxysilane, η-butyl or
Isobutyl-triethoxy- or trimethoxysilane and the like.

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As organofunctional silicon silanes that increase adhesive strength In accordance with the invention, preference is given to general ones formula

R _n Si - A - Z
ι ι
hn

used, in which R is a hydrolyzable radical such as Cl, OR (R = ö-j _ -je --A- ¹ ^ yl ^re S ^ j optionally containing heteroatoms such as -O- or -S-),

R is an alkyl radical with 1 to 18 carbon atoms, A is a divalent alkylene radical with 1 to 10 carbon atoms, the

may optionally be branched, and Z is a functional radical such as -CH-CHp or -C = C- or

I 1 I I I

NRR,

v / obei R ^! 'is H or aminoalkyl with 2 to 8 carbon atoms in the alkyl radical and R *''is H or R, and η is 1 to 3 and ρ is 1 or, in the case of Z = - CH-CH ₂ 0.

Such organofunctional silicon silanes are accordingly bifunctional. In addition to at least one hydrolyzable group that reacts in conjunction with the glass surface, must also at least one reactive group can be present which can react with the partially acetalized PVA film. As examples are called:

Vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (| /; - methoxyethoxy) silane,% ^A -methacryloxypropyltrimethoxysilane,, ^ - glycidyloxypropyltrimethoxysilane, y-aminopropyltriethoxyfjilane and the like.

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According to the invention, a preferred silicon-functional silane is used Isobutyltrimethoxysilane and preferably Y'-glycidyloxypropyltrimethoxysilane as the organofunctional silicon silane.

The process according to the invention is based on partially acetalized Polyvinyl alcohol resins which still contain OH groups. Preference is given to using those which contain 10 to 25% by weight, preferably 17 to 23% by weight, of vinyl alcohol radicals. Deilbutyralized polyvinyl alcohol is preferred used.

In the case of composite safety panes that are used in the construction sector, for example, as window panes or as partition walls, the The adhesive strength of the inorganic glass on the film is of crucial importance. In the case of careless destruction, it must Adhere the glass firmly to the film to avoid severe cuts. Composite panes with high pummel values are desired, therefore, preferably using partially acetalized polyvinyl alcohol films (hereinafter partially acetalized PVA films called), whose adhesive strength is achieved through the addition of organofunctional silicon silanes or their mixtures to the corresponding partially acetalized PVA resins was set to the highest possible pummel values.

The method according to the invention has the advantage that the adhesive force of a partially acetalized PVA film on inorganic glasses can be adjusted to an optimal pummel value adapted to the particular application. For example, a partially acetalized PVA Har ζ batch can be used in which, on the basis of a

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- ίο -

was found to / partially acetalize to a glass PVA film / glass composite leads due to a high Pummelwerte was suitable as a composite safety window in the construction sector, but not as a windshield in motor vehicles is, by adding an amount determined in the gate test, of a silicon-functional silane reducing the adhesive force in "windshield quality" being transformed. In the opposite case, a partially acetalized PYA resin can be a "Windshield quality" into one with "construction sector quality" by adding an amount determined in a preliminary test a silicon-organofunctional silane. You are therefore largely independent of the respective quality the partially acetalized PVA resins to be processed. It is not necessary to keep double stocks, as was usually the case up to now.

Foil waste from the composite pane industry is common taken back by the film manufacturers and after a preparation process together with fresh goods in the extruder processed into new foil.

However, this makes the quality of the new films more uncontrollable Way influenced. In most cases, the waste is not strictly classified beforehand according to the windshield or construction sheet film quality delivered sorted. An indefinable mixture of waste therefore leads to foils with an undefined content Adhesion to the glass .. According to the invention, it is now possible by means of a suitable combination of those used according to the invention Silane types also tiit unsorted waste to foils to process a defined adhesive force.

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Experiments with various partially acetalized PVA film compounds unknown and different quality with regard to the pummel values hit namely that you get the desired goal can be achieved if the film mass is a mixture consisting of an organofunctional silicon which increases the adhesive force Silane and a silicon-functional silane which reduces the adhesive force.

The amount of silane to be added or the type of silane to be added depend both on the intended use of the composite panes and on the properties of the one to be modified partially acetalized PVA resin. It depends on the pummel value of the unmodified partially acetalized PVA polie.

The adhesive force of a pane of glass on a plasticizer-containing, partially acetalized polyvinyl alcohol film is determined by the so-called "pummel test". A laminated glass pane (glass / partially acetalized PVA film / glass) in the size of approx. 150 300 mm is cooled for ^{approx. 2 to 8 hours at -18 0} C 0.5 ^{0 C} ° placed an inclined metal block and hammered with a flat head hammer until the glass is pulverized. The test area is approx. 100 χ 150 mm in size. The adhesion is assessed on a scale from 0 to 10. These values mean:

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free film area

Pummelwert

100

. 5

0 1 2 3 4 5 6

7 8

9 10

The visual assessment is facilitated by the fact that in addition to the The specified pummel values are also shown on the scale next to the respective pummel value. It has shown, that this - not quantitative - pummel test is completely sufficient for practice, and that one based on the visual assessment can adjust the desired adhesive force with sufficient accuracy.

In the event that the pummel value of the resin to be modified not predetermined due to the addition of foil waste it is expedient to add a minimum amount of a silicon-organofunctional silane which results in the highest pummel value leads; At the same time, the amount of silicon-functional silane is added that is based on calibration tables for the Setting the desired pummel value are necessary. But you can also proceed in such a way that, before you start a new Batch of partially acetalized PVA resin processed into a film, a Terbund disc test specimen produced and its pummel

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worth noting. On the basis of this defined pummel value, the value previously determined empirically in series tests can then be used Amount of the silane suitable for the desired purpose can be added.

In practice "the silane levels are between about 0.005 and $ 0.2 wt .- based on 100 parts by weight of film compositions.

The silanes to be added according to the invention can be partially acetalized Polyvinyl alcohol resins before processing. be added to a film. For example, the in Partly acetalized PYA resin particles with the silanes, which are kept in constant motion and do not yet contain a plasticizer or silane solutions or dispersions. The solvents or dispersants used are preferably those which behave inertly or largely inertly towards the partially acetalized PVA resin. As a solvent, e.g. water or water / alcohol mixtures can be used. If necessary, the solvent or dispersant is used in a subsequent Removed drying process, so that a free-flowing partially acetalized PVA resin is present, which is then used by the film manufacturer after adding the required amount of plasticizer is processed into the film by processes known per se, preferably by the extrusion process.

However, the preferred procedure is to mix the silanes and the plasticizer with the partially acetalized polyvinyl alcohol resins during processing into a film, e.g. into a Extruder cDmpounded in the melt. In this procedural

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wisely, it is advisable to first add the silanes to the To dissolve or disperse plasticizers before the silane / plasticizer mixture is partially acetalized to be extruded Adding PVA resins. Plasticizers in which the silanes are soluble are preferred. For the method according to the invention the plasticizers mentioned at the beginning of the prior art are suitable, the triethylene glycol ~ di- (2-ethylbutyrate) the preference is given. The amounts of plasticizer to be added correspond to those for the production of partially acetalized PVA polien usual quantities.

The modified partially acetalized PVA films according to the invention are preferably used as adhesive films. This use takes place in the usual way in the composite safety window industry Procedure.

A partially butyralized polyvinyl alcohol film modified with silanes is preferably used as the adhesive film, which (a) a plasticizer content of approx. 18 to approx. 65 parts by weight, preferably 33 to 44 parts by weight per 100 parts by weight of PVB, (b) a water content of 0.2 to 0.9 wt .- # and (c) an OH group content, calculated as vinyl alcohol, of 10 to 25, preferably from 16 to 23 wt .- ^.

The composite safety panes, in which the partially acetalized PVA poles modified according to the invention are used, consist of two or more glass layers and one ^{arranged between two glass layers s} n , according to the invention

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Silanes-modified, partially acetalized, plasticizer-containing PVA film. Optionally, in a glass / glass composite, a The glass layer can be replaced by a plastic layer, e.g. made of an amorphous polyamide (see e.g. 'DBP 1 596 781). Included it is up to the goal to arrange two adhesive sheets between the two layers, with the one next to the glass layer According to the invention, the adhesive film has been modified with silanes and the adhesive film resting on the plastic layer is unmodified. In the case of composites that consist of more than two load-bearing layers, e.g. glass / plastic / glass composites, a similar method can be used Act wisely. For glass / plastic / plastic / glass bonds expediently, only an unmodified, partially acetalized PTA film is used between the plastic / plastic layers Adhesive film used.

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- 16 -

Examples

The dielectric strength mentioned in the examples is after

[DIN 52 306 (February 1973) or USA S, Z 26.1, test number 26

; ' (1966) tested with the help of the ball fall.

; The change in the pummel shown in the following tables

values due to the addition of silane were

j disks made in the following way

' became:

j The addition of the silane to the PVB resin (OH group content, calculated as vinyl alcohol 18.5 wt .- $) took place during the production of PVB polien in the extruder. The PVB resin used j of Table 1 came from a different batch than that

of table 2.
j In the examples, composite panes were tested, which two

3 mm thick glass panes and a 0.76 mm thick PVB-IOlie in between.

The composite panes were produced at a temperature of 130 to 135 ° C. and a pressure of 10 to 15 kp / cm and a pressing time of 10 to 30 minutes.

Triethylene glycol di (2-ethylbutyrate) was used as a plasticizer in an amount of 35 parts by weight per 100 parts by weight of PVB resin used.

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- - 2Λ 10.153

Table 1

Gev /.-^ N 'm weight -70 mm

Example Silane 'Pummel Ball Fall- Water Polien-

hb'he i.d. Foil starch

1 0 10 1.50 0.5 0.76

2 0.3 7 2.50 0.5 0.76

3 0.4 5 4.00 0.5 0.76

4 0.5 3 5.50 0.5 0.76

*) Isobutyl-trimethoxy-silane

j Taftelle 2

■ As the following examples show, the adhesive force is important tend to increase.

Example silane ^} pummel water id film

5 0 1 0.5

6 0.005 3 0.5

7 0.01 5 0.5

8 0.1 10 0.5

*) IT-glycidyloxypropyl-trimetb-oxy-silane

Examples 9 and 10 relate to the use of iOli fall off together with fresh, partially butyralized polyvinyl alcohol hara. The pummel value is due to the changing composition of foils Eggasse Undefined:

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! Example 9 Silane 1 = 0.1 wt. -F> + Silane 2 = 0.45 wt .- # Pummel = 5

jExample 10 Silane 1 = 0.1 wt. -% + Silane 2 = 0.6 wt .- ^ Pummel = 2

jIt means:

Silane 1 = / '- glycidyloxypropyl - trinietlioxy-silane ι jSilane 2 = isobutyl-trimethoxy-silane I j The quantities in the tables refer to sieve, to 100 weight / fcs-

: share polien mass.

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Claims (1)

- 19 P ate η claims 1 J method for adjusting the adhesive force of plasticizer-containing partially acetalized polyvinyl alcohol films on inorganic Oäsern to the pummel values required for the respective application, characterized in that the partially acetalized polyvinyl alcohol resin is either before or during processing into a film by methods known per se predetermined amounts a) a silicon-functional silanes which reduce the adhesive force or a mixture of different silicon-functional silanes Silanes or b) a silicon-organofunctional silane which increases the adhesive force or a mixture of silicon-organofunctional Silanes or c) a mixture of at least one silicon-functional silane with at least one silicon-organofunctional ^! Silane adds. 2. The method according to claim 1, characterized in that the silicon-functional silanes are those of the general formula \ - ^Si - ^R i - η ' uses, in which R identical or different, saturated, straight or branched alkyl radicals with 1 to 18 carbon atoms, R halogen, preferably Cl, or identical or different, saturated alkoxy groups with 1 to 8 carbon atoms, the given- 509836/1007 optionally interrupted by heteroatoms, such as -0- or -S- are, and η is 0 to 3. 3. The method according to claim 1, characterized in that the organofunctional silicon silanes are those of the general formula R _n Si - Ap - Z ^R 3 - η uses, in which R is a hydrolyzable radical, such as Cl, OR '' (R = C AQ -Alley! radical, optionally containing heteroatoms such as -0- or -S-), R is an alkyl radical with 1 to 18 carbon atoms A is a divalent alkylene radical with 1 to 10 carbon atoms, the may optionally be branched, and Z is a functional radical such as -CH-CH ₂ or -C = C- or Ii ill ^ n NRR, ^U ι ι where R is H or aminoalkyl with 2 to 8 carbon atoms t I t It in the alkyl radical and R is H or R, η is 1 to 3 and ρ is 1 or, in the case of Z = -CH-CH _{2 O.} ^! 4. The method according to claim 1 or 2, characterized in that - That the silicon-functional silane is isobutyl-trimethoxysilane begins. 509836/1007 _ _ _2A.1_pl_53 \ 5. The method according to claim 1 or 3, characterized in that y-glycidyloxypropyl-trimethoxy-silane is used as the organofunctional silicon silane. I 6. The method according to claim 1 to 5> characterized in that I one as a partially acetalized polyvinyl alcohol a PoIy-J vinyl butyral is used, which is still about 10 to 25 preferably 17 to 23 wt .- ^ contains vinyl alcohol residues. I 7. Laminated safety panes, which are made using the according to i one of claims 1 to 6 modified partially acetalized polyvinyl alcohol films were produced. 509836/1007