Use of a composition containing a carbodiimide and a polyester plasticizer as a plasticizer for polyvinyl chloride or polyvinyl chloride copolymers

Abstract

The invention relates to a roofing membrane containing a base polymer. To improve resistance to hydrolysis, the membrane contains an ester-based polymeric plasticizer and at least one hydrolysis stabilizer with at least one carbodiimide.

Description

[0001] The invention relates to the use of a composition containing at least one carbodiimide and at least one polyester plasticizer as a plasticizer for polyvinyl chloride or polyvinyl chloride copolymer. The invention is explained using the example of the use of this plasticizer in a PVC roofing membrane; however, roofing membranes themselves and their manufacture are not the subject of this invention and are not claimed herein.

[0002] Waterproofing membranes, especially roofing membranes, typically contain a base polymer based on polyvinyl chloride (PVC), polyvinyl chloride copolymers, ethylene-vinyl acetate terpolymers, ethylene-vinyl acetate copolymers (e.g., ethylene / n-butyl acrylate / carbon monoxide or ethylene / vinyl acetate / carbon monoxide), and a plasticizer with sufficiently good plasticizing properties. When selecting a membrane, it is also important to ensure, among many other requirements, that it offers particular resistance to water-based media. Furthermore, polymer-plasticized and internally flexible PVC / EVA membranes should exhibit resistance to media, especially those based on bitumen, polystyrene, and polyurethane; interactions in the form of migration should be minimized.

[0003] When using ester-based plasticizers, such as phthalate esters, or polyester-based polymer plasticizers, e.g., based on adipic acid or sebacic acid as the polymer plasticizer, hydrolysis is possible. Through hydrolysis, the long-chain plasticizers are degraded into the starting materials alcohol and dicarboxylic acid, resulting in the migration of the degradation or hydrolysis products to the surface of the roofing membrane. Simultaneously, the concentration of the plasticizing component decreases, leading to a reduction in the roofing membrane's flexibility.

[0004] The degradation by hydrolysis can be improved by the use of special hydrolysis stabilizers - which are H+ ion / proton scavengers.

[0005] Phthalic acid esters are commonly used on a large scale as plasticizers for waterproofing membranes that are not compatible with bitumen. The mechanism of hydrolysis is also known in this case.

[0006] WO 20017 / 096356 A1 concerns a plastic film comprising a mixture of polyvinyl chloride (PVC) and at least one thermoplastic polyurethane, and its use for sealing or lining containers for storing or conveying biodiesel. WO 2007 / 096356 A1 describes only films, without any mention of a roofing membrane.

[0007] CH 55 10 944 relates to a process for producing thermoplastic polymer compounds based on polyurethane-polyvinyl chloride, in which polyvinyl chloride is first reacted intensively with the starting materials required for the production of polyurethane below the reaction temperature of non-polyvinyl chloride and then gradually reacted with heat to form a thermoplastic polyurethane containing polyvinyl chloride. CH 55 10 944 describes only films and test plates, without any mention of a roofing membrane.

[0008] The present invention is based on the objective of providing a hydrolysis stabilizer that leads to sufficient hydrolysis resistance of plasticizers.

[0009] At the same time, it should be ensured that both the mechanical properties and all essential properties of a roofing membrane - such as weather resistance, processing behavior (seam joining) - are not adversely affected.

[0010] The invention provides for the use of a composition according to the claims of this patent to solve the problem.

[0011] During the plasticizer manufacturing process, not all free acid groups of the carboxylic acid are completely converted into ester groups through polymerization. These free acid groups are characterized by the so-called "acid number." In general, the acid number can be described as encompassing all acidic functional groups that can be neutralized by potassium hydroxide.

[0012] Ester-based plasticizers, such as polyester-based polymer plasticizers, are susceptible to acid-catalytic hydrolysis. The degradation of the polymer plasticizer depends on the acid number of the starting material, i.e., the polymer plasticizer itself. Experiments have shown that the higher the acid number of the starting material, the faster the plasticizer degradation occurs.

[0013] Consequently, the acid values ​​should be set as low as possible. Preferred ester-based polymer plasticizers have an acid value of 0.1–1, preferably 0.3–0.5.

[0014] In particular, it is intended that a polyester-based plasticizer, especially one based on adipic or sebacic acid, will be used.

[0015] In particular, the invention provides that the following raw materials are used as starting materials for the polyester-based plasticizer in wt.%: Dicarboxylic acid 52.0 ± 6.6, preferably 55.4 ± 3.0, particularly preferably 57.1 ± 1.9 Neopentyl glycol 22.0 ± 20.0, preferably 15.0 ± 7.0, particularly preferably 14.1 ± 2.1 further Diol 13.3 ± 12.0, preferably 18.1 ± 6.0, particularly preferably 17.3 ± 2.9 Alcohol mixture 12.7 ± 11.0, preferably 11.5 ± 6.0, particularly preferably 11.5 ± 2.3 where the total sum is 100.

[0016] In particular, it is stipulated that the starting materials in wt.% are the adipine or sebacic acid ester: at least one dicarboxylic acid from the group consisting of adipic acid, sebacic acid 52.0 ± 6.6, preferably 55.4 ± 3.0, particularly preferably 57.1 ± 1.9, neopentyl glycol 22.0 ± 20.0, preferably 15.0 ± 7.0, particularly preferably 14.1 ± 2.1, at least one further diol from the group consisting of butanediol, propanediol 13.3 ± 12.0, preferably 18.1 ± 6.0, particularly preferably 17.3 ± 2.9, at least one alcohol mixture from the group consisting of isononanol, isodecanol 12.7 ± 11.0, preferably 11.5 ± 6.0, particularly preferably 11.5 ± 2.3, where the total sum is 100.

[0017] In other words, the end-group closure can be isononanol or isodecanol.

[0018] It should also be mentioned that isononanol and isodecanol can each be a mixture of isononanol or isodecanol.

[0019] In particular, it is intended that the main components of isononanol consist predominantly of 1-nonanol, monomethyl octanols, dimethylheptanols and monoethylheptanols.

[0020] Surprisingly, it has been found that when a hydrolysis stabilizer contains at least one aliphatic carbodiimide according to the claims, there is a significant improvement in hydrolysis resistance, while at the same time the essential properties remain unchanged compared to sealing membranes that do not contain a corresponding hydrolysis stabilizer.

[0021] In particular, it is provided that the proportion in wt.% of the hydrolysis stabilizer containing at least one carbodiimide is 0.1 - 5, in particular 0.5 - 2.

[0022] In a further development of the invention, it is provided that, in addition to the hydrolysis stabilizer containing at least carbodiimide, a thermostabilizer is included. Suitable thermostabilizers include, in particular, Ca / Zn one-pack stabilizers, Ba / Zn, or an organic thermostabilizer such as OBS® from Chemson.

[0023] A one-pack calcium / zinc stabilizer preferably consists of a) Ca / Zn (from stearates, octoates, behenates, carboxylates) with Ca / Zn in a ratio of 2:1 to 1:1, preferably 2:1, preferably 7.5 to 20% each, in particular 15% Ca and 10% Zn, b) 50–70 wt.%, preferably 55–65 wt.%, in particular 60 wt.% hydrotalcite, c) 0.2–8 wt.%, preferably 0.5–7 wt.%, in particular 5 wt.% lubricant, d) 0.2–6 wt.%, preferably 0.5–4 wt.%, in particular 2 wt.% antioxidants, and e) 0.2–6 wt.%, preferably 0.5–4 wt.%, in particular 3 wt.% flow aids.

[0024] The use of hydrotalcite is characterized by particularly low water absorption and increased stability. In combination with Ca / Zn, high weather resistance is achieved. Lubricants are included to facilitate processing in machinery. Antioxidants enhance thermal stability. Flow aids serve as incorporation and dispersion aids.

[0025] Preferably, this is at least one carbodiimide selected from the group consisting of monomeric aliphatic carbodiimides, oligomeric aliphatic carbodiimides, polymeric aliphatic carbodiimides, monomeric aromatic carbodiimides, oligomeric aromatic carbodiimides and polymeric aromatic carbodiimides.

[0026] The aliphatic carbodiimides used according to the invention can vary widely. Suitable carbodiimides are described, for example, in EP 0 628 541, DE 43 189 79 A1, or DE 198 21 666 A1. Particularly suitable carbodiimides are described, for example, by the general formula: where n = 1 to 20 and R5 and R6 are methoxylated polyethylene glycol residues of the formula: -(EO)m-OCH3 with m = 1 to 20.

[0027] The molar ratio of added carbodiimide groups to the initial acidity of the ester used can vary widely and, according to the invention, is preferably in the range of 20:1 to 1:10, preferably 10:1 to 1:2.

[0028] According to a further embodiment, the molar ratio of added carbodiimide groups to the initial acidity of the ester used is in the range of 20 : 1 to 1 : 10.

[0029] In particular, a roofing or sealing membrane comprises a base polymer, a polymeric plasticizer based on an adipic acid or sebacic acid polyester with an average molecular weight of 3,000 to 12,000 and / or a monomeric plasticizer, e.g., based on phthalic acid esters, and / or a polyacrylate and / or a rubber-like polymer, preferably comprising (a) 40 to 80, preferably 50 to 80, and particularly 55 to 75 wt.% butyl acrylate or optionally a mixture of butyl acrylate and 2-ethylhexyl acrylate containing up to 40 wt.% 2-ethylhexyl acrylate, (b) 5 to 35, preferably 5 to 20 wt.% at least one substance selected from the group consisting of methyl methacrylate, ethyl methacrylate, methyl acrylate, or ethyl acrylate, and (c) 4 to 30, preferably 6 to 30, particularly 10 to 25. wt.% acrylonitrile, (d) from 3 to 25 preferably 5 to 18, in particular 8 to 14 wt.% styrene, (e) from 0.5 to 8, preferably 1 to 5, in particular 2 to 4 wt.%-% of a maleate semi-ester soap and 0.25 to 8, preferably 0.5 to 4, in particular 1 to 3 wt% of a crosslinking agent.

[0030] Polyvinyl chloride (PVC) or polyvinyl chloride copolymers are used as base polymers. Mixtures of these can also be used. The base polymer is used, for example, in proportions of 20 to 60 wt.%, preferably 35 to 55 wt.%. All values ​​given in wt.% refer to the entire composition.

[0031] Adipic acid or sebacic acid polyester is used, for example, in proportions of 20 to 45 wt.%, preferably 25 to 35 wt.%. Sealing membranes made from compositions with such proportions of adipic acid or sebacic acid polyester exhibit particularly good compatibility with bitumen and polystyrene, as well as high migration resistance, even at elevated temperatures. High impact strength and high tensile impact strength are also positive properties. Tensile impact strength is determined in accordance with DIN EN ISO 8256 and DIN 53453.

[0032] Furthermore, the composition for manufacturing a sealing membrane can contain a polyacrylate. Examples of suitable polyacrylates include ethyl butyl acrylate, butyl acrylate, copolymers of acrylic acid and vinyl chloride, MMA, or PMMA. The polyacrylate component significantly improves the aging and weather resistance of the sealing membranes and is primarily used in the top layers of two-layer or multi-layer systems.

[0033] Of the polyacrylates mentioned above, the use of butyl acrylate is particularly preferred.

[0034] In the composition, the polyacrylate can be used in the form of butyl acrylate particles coated with PMMA or MMA. These butyl acrylate particles preferably have an average particle size of 100 mm or less; a more preferred average particle size is between 5 and 40 mm.

[0035] Another polyacrylate is a copolymer of acrylic acid with vinyl chloride, in particular a graft copolymer of these compounds. Such graft copolymers are preferably used as granules with a particle size between 0.25 and 5 mm, particularly preferably between 1 and 2 mm.

[0036] The polyacrylates used have an average molecular weight of 5,000 to 120,000, preferably of 10,000 to 100,000.

[0037] The polyacrylates used in these compositions are, for example, in proportions of 3 to 30 wt.%, preferably 8 to 25 wt.%, and particularly 10 to 20 wt.%. Sealing membranes made from compositions with such proportions of polyacrylates exhibit particularly high aging resistance and can also be processed very well at low temperatures.

[0038] The use of the rubber-like polymer marketed under the trade name Sunigum® by Goodyear or Omnova Solutions is particularly preferred. In the roofing membranes according to the invention, the polymer is used in amounts of 1 to 30, preferably 5 to 20, and particularly 8 to 15 wt.%.

[0039] Adipic acid polyester is primarily composed of adipic acid and 1,4-butanediol. Variants containing 1,3-propanediol are also common.

[0040] The composition of roofing or sealing membranes may also contain further additives such as fillers, pigments, dyes, UV stabilizers, heat stabilizers, fungicides, biocides, processing aids, and additional plasticizers. These additional plasticizers are preferably low-molecular-weight, monomeric plasticizers such as phthalate esters. Plasticizers commonly known from the prior art and compatible with PVC can also be used. Typical plasticizers include, for example, derivatives of sylvite or acetic acid such as cumylphenyl acetate, derivatives of adipic acid such as benzyl octyl adipate, dibutyl adipate, diisobutyl adipate, di-(2-ethylhexyl) adipate, diisononyl adipate, derivatives of azelaic acid, benzoic acid derivatives, polyphenyl derivatives, citric acid derivatives, epoxidized fat derivatives, and glycol derivatives. Furthermore, bio-based plasticizers can also be used.Plasticizers that contain (at least partially) renewable raw materials, such as those described in EP 3 156 447 A1.

[0041] Preferably, however, the composition contains less than 30 wt.% of additional plasticizers, particularly preferably less than 15 wt.%.

[0042] To increase the thermal stability of the webs, heat stabilizers known from the prior art, such as Ba / Zn stabilizers, preferably Ca / Zn stabilizers, may be included. In addition, UV stabilizers, such as oxalanilides, amides, titanium dioxide, carbon black, in particular Tinuvin® and / or Chimasorb®, and / or especially NOR-HALS stabilizers, may also be included. The stabilizers are typically present in amounts of 0.01 to 10%, preferably 0.1 to 5% by weight. The total amount of stabilizers typically does not exceed 20% by weight of the mixture.

[0043] Tinuvin®, preferably Tinuvin XT 833, acts not only as a UV stabilizer but also as an acid scavenger, thereby improving hydrolysis. The stabilizer Tinuvin XT 833 additionally binds hydrochloric acid and improves both aging behavior and hydrolysis stability.

[0044] Tinuvin XT 833 is listed in the safety data sheet as a product containing 40-60% by weight of CAS No. 25973-55-1, which corresponds to the chemical name 2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol. Accordingly, substances with a composition similar to Tinuvin XT 833 but marketed under different product names may also be used.

[0045] The webs can contain conventional fillers known from the prior art, such as chalk, talc, silica, or kaolin. The amount of filler is 0 to 15%, preferably 1 to 10% by weight.

[0046] Chalk is preferably used in coated form. Kaolin improves both abrasion and chemical resistance.

[0047] Kaolin also has an acidic character, which can be described, for example, by its pH value: here, the average pH value is between 4.5 and 6.5. For comparison, acetic acid has a pH value of 4.75. Accordingly, in this application, the use of chalk, especially coated chalk, is preferred to keep the acid content in the formulation low.

[0048] In addition, other common ingredients may be included, such as lubricants, processing aids, gelling agents, UV converters, UV stabilizers or biocides such as thiazolin derivatives, tributyltin, chloroisothiazolin, isothiazolin derivatives being particularly preferred.

[0049] A roofing or sealing membrane can also have fiber reinforcement. This fiber reinforcement can consist of a nonwoven fabric, a woven fabric, and / or a woven fabric. The fiber reinforcement can be made from selected fibers, such as glass, mineral, polyester, polyamide, polyethylene, polypropylene fibers, or mixtures thereof.

[0050] In particular, a roofing or sealing membrane has an internal insert or reinforcement.

[0051] A roofing or sealing membrane can also be equipped with a cold self-adhesive layer on at least one side.

[0052] Alternatively, a roofing or sealing membrane can be coated with an adhesive on at least one side. In this case, the familiar adhesive systems are suitable, in particular acrylate adhesives, polyurethane-based adhesives, or bituminous self-adhesives.

[0053] It is also possible to apply the cold self-adhesive coating or pressure-sensitive adhesive to both sides of a roofing or sealing membrane. Likewise, it is possible to equip one side of a roofing or sealing membrane with a cold self-adhesive coating and the other side with a pressure-sensitive adhesive.

[0054] A combination with at least one hydrotalcite can also be used as a thermostabilizer, which limits water absorption and additionally improves hydrolysis stability.

[0055] Tests have shown that the effectiveness against the release of hydrochloric acid (HCl) depends on the oxirane content of the high molecular weight glycidyl ester or the epoxidized soybean oil.

[0056] In particular, for a standard ESBO (epoxidized soybean oil), a material is selected that has the highest possible oxirane content.

[0057] Preferably, an epoxidized soybean oil or a high-molecular-weight glycidyl ester with a high oxirane content is selected. The oxirane content should be between 5 and 12 wt.%, preferably between 8 and 11 wt.%, and particularly > 9 wt.%.

[0058] A high oxirane content particularly improves hydrolysis resistance and increases the binding of hydrogen chloride, as the following formula illustrates:

[0059] For both of the above-mentioned processes, a homogenized final mixture is produced by mixing the two components. Since ester-based polymer plasticizers and high-molecular-weight glycidyl esters, such as epoxidized soybean oil, are highly viscous liquids, mixing should take place in a stirred tank at an elevated temperature. The temperature should be in the range of 50 to 100 °C, preferably between 70 and 90 °C.

[0060] Furthermore, it is preferable to mix the liquid hydrolysis stabilizer into the higher-viscosity liquid, i.e., to add it to the polymer plasticizer in the agitator while stirring. The polymer plasticizer should first be pre-heated to a temperature that results in a lower viscosity liquid and thus better transportability. Subsequently, the temperature of the polymer plasticizer is kept constant by the frictional energy during the stirring process and by heated walls of the mixing vessel, ensuring optimal incorporation of the hydrolysis stabilizer.

[0061] The ratio between the higher viscosity liquid (polymer plasticizer and / or epoxidized soybean oil) and the liquid hydrolysis stabilizer can be varied. A ratio of 3:1 is preferred, meaning that an addition of 4 wt% corresponds to an addition of 3 wt% high viscosity liquid and 1 wt% liquid hydrolysis stabilizer.

[0062] Compounding, or the preparation of mixtures, or dry-blending, of PVC formulations is generally known to those skilled in the art and is described in detail, for example, in the following report: "Industrial Compounding Technology of Rigid and Plasticised PVC" by W. Henschel and P. Franz (PVC Technology, Fourth Edition 1984, WV Titow). Batch mixing has become the standard method for compounding flexible PVC products, usually employing a heating / cooling mixer combination.

[0063] A particularly thorough blending of the individual formulation components is achieved when the following mixing process is used: All solids, i.e., the base polymer as well as other solid additives such as fillers and pigments, are placed together in the hot mixer and pre-mixed for approximately 1 to 1.5 minutes. The first half of the plasticizer is then added to the formulation and mixed to a temperature of 70 to 90 °C. The second half of the plasticizer is then added to the hot mixer and mixed to a temperature of, for example, 110 to 185 °C to obtain a dry final mixture. The mixture is then transferred to the cooling mixer and cooled to a lower temperature, preferably 40 to 60 °C. Plasticizer-compatible products such as acrylates and / or rubber-like polymers can be added in the cooling mixer.

[0064] Furthermore, it should be noted that processing temperatures should be chosen to be 5 to 10 °C higher than the final temperature of the mixture.

[0065] It should also be noted that the described mixing procedure can be used, for example, for mixing the following process: Add the solids and / or minute quantities of liquids to the hot mixer – these materials can be premixed, although this is not strictly necessary. Add the first half of the plasticizing component to the system and heat it to temperatures between 65 and 90 °C. Then add the second half of the plasticizing component to the system and mix until a temperature of 110 to 190 °C (depending on the mixing unit). Transfer to a cooling mixer where products compatible with plasticizers can be added.

[0066] For example, a mixture preparation for the following composition (Z 1 ) is given: Suspensions PVC K70 at 45.0 - 55.0%, chalk at 3.0 - 10.0%, a plasticizing component based on a polymeric plasticizer based on an adipic acid polyester and another plasticizer based on a monomeric plasticizer (a phthalic acid ester) at 28.0 - 38.0%, as well as at 1.5 - 7.0%, a Ca / Zn stabilizer at 0.5 - 4.0%, a co-stabilizer based on an epoxidized soybean oil at 1.5 - 5.0%, a grey pigment content of 2.0 - 8.0% and a hydrolysis stabilizer based on carbodiimide components at 0.2 - 5.0%.

[0067] At the start of the mixing process, the solids—i.e., PVC, chalk, and the pigment—are added to the mixing vessel (i.e., the hot mixer). The quantities are weighed using a pre-controlled weighing tray system and added accordingly. These materials are pre-mixed for approximately 1 to 1 minute without special temperature control. Then, the first half of the plasticizing components is added to the initial mixture and mixed to a temperature of 70–90 °C, with the heat generated by shearing of the individual components. At 70–90 °C, the second part of the plasticizing component is added and mixed to a temperature of 110–165 °C, preferably 115–130 °C, to obtain a homogeneous and finely dispersed dry blend without agglomeration. The dry blend mixture is then transferred to the cooling mixer and cooled down in a container, either by heat or water.

[0068] The epoxidized soybean oil can be added either to the solid components or when adding the first or second portion of the plasticizer. The hydrolysis stabilizer can be added either The hydrolysis stabilizer can be pre-mixed into the epoxidized soybean oil, for example using a previously connected mixing tank, and this tank can be mixed in during the addition of the solid components or during the addition of the first or second part of the plasticizing component; alternatively, the hydrolysis stabilizer can be added directly to the solid components; in a further embodiment, it can be incorporated into the plasticizing component beforehand, for which, for example, a premixing tank for the plasticizing component can be used.

[0069] In a modified composition (Z 2), an acrylate is added to the composition at a rate of 5.0–15.0%. This acrylate can be added either during premixing the solid components or later during transport to the cooling mixer. The second option is preferred to prevent the plasticizer from diffusing into the acrylate and thus minimize the plasticizer uptake by the PVC. Furthermore, adding the acrylate later prevents blockage and any resulting impairment of function.

[0070] It is therefore possible to incorporate the hydrolysis stabilizer containing at least one carbodiimide directly into the polymer plasticizer or by incorporation into epoxidized soybean oil or into the masterbatch of the mixture or composition based on Ca / Zn One-Pack stabilizer, Ba / Zn, whereby the liquid form is generally preferred, even if the powder form is to be chosen as a component of the masterbatch.

[0071] For the production of roofing membranes, the final mixture (end-dry-blend mixture) can be processed either directly via a twin-screw extruder or via a calender.

[0072] An intermediate step of granulation is also possible.

[0073] Further details, advantages and features of the invention will become apparent not only from the claims and the features to be derived therefrom - individually and / or in combination - but also from the following description of examples.

[0074] The stabilizing effect of the hydrolysis stabilizer according to the invention is explained using the following exemplary embodiments.

[0075] It is well known that ester-based plasticizers, such as polyester-based polymer plasticizers, are susceptible to acid-catalytic hydrolysis. The rate of degradation depends on the acid number of the starting material, i.e., the polymer plasticizer. In other words, the higher the acid number of the starting material, the faster the plasticizer degrades.

[0076] During the plasticizer manufacturing process, free acid groups are formed, which are characterized by the so-called "acid number". In general, the acid number can be described as encompassing all acidic groups that can be neutralized by potassium hydroxide.

[0077] Therefore, the time-dependent change in the molar mass distribution (molecular weight distribution) of two different adipic acid-based polyester plasticizers was determined using gel permeation chromatography (GPC). First, a type I polyester plasticizer (polyester-based plasticizer based on adipic acid with end-group termination using isononanol) was used, whose acid number of the starting material was 0.4 mg KOH / g. The acid number of a second type II polyester plasticizer (polyester-based plasticizer based on adipic acid with end-group termination using isononanol and with a different molar ratio in terms of the composition of the diols used compared to type II) was 0.66 mg KOH / g. The table shows that the number-average molecular weight is...The weight-mean molecular mass weight increases over time, with the increase being greater for type I than for type II, meaning the weight loss was less for those plasticizers whose initial acid number was smaller, as shown in the table below: Polyester plasticizers type I 1)< . Storage time 0d 28d 42d 56d 70d Mn 3100 2200 1700 1400 1200 Mw 6600 4600 3400 2700 2200 Weight loss [%] 0 -0,5 -4,42 -16,3 -23 1) < polyester-based plasticizer based on adipic acid and end-group termination using isononanol Polyester plasticizer type II 2) Storage time 0d 28d 42d 56d 70d Mn 2600 1800 1400 1200 1000 Mw 5600 3700 2700 2100 1700 Weight loss [%] 0 -0,5 -7,1 -17,8 -23,5 2)< polyester-based plasticizer based on adipic acid, an end-group termination using isononanol and a modified molar ratio regarding the composition of the diols used compared to type I.

[0078] The change in weight is also reflected accordingly in the change in acid number. This results from the Figure 1 , in which the acid value mgKOH / g is plotted against time. Curve 10 represents the change in the acid value over time of a polyester-based plasticizer based on adipic acid, to which no hydrolysis stabilizer has been added.

[0079] In contrast, if a hydrolysis stabilizer according to the invention is added to the polyester plasticizer, containing 1 wt% carbodiimide based on the plasticizer, a considerably lower increase in the acid number is observed, as shown in curve 12 in the Figure 1 clarifies.

[0080] It should be noted that only the plasticizer was considered in each case. For the measurements, the polyester plasticizer was mixed with 10 wt% water and boiled under reflux (T = 100 °C).

[0081] Corresponding results are also confirmed by the following (comparative) tests using roofing membranes containing a base polymer, a polymeric plasticizer in the form of an adipic acid polyester and a polyacrylate.

[0082] So wurden 1,5 mm dicke handelsübliche bitumenverträgliche PVC Dachbahnen entsprechend der Stoffzusammensetzung beschrieben in DIN SPEC 20000-201 Tabelle 2 - "Werkstoffbezeichnungen und Zusammensetzung der Kunststoffe und Elastomere" als PVC Bahn durch Extrusion hergestellt, wobei hier ein Adipinsäurepolyester als sog. Polymerweichmacher eingesetzt wurde, wobei der Acrylatgehalt > 3% beträgt (Zusammensetzung Z 3 ): PVC 45 bis 55 %, Kreide 4,0 bis 10,0 %, Acrylat 3,0 - 12,0 %, Polymerweichmacher 27,0 bis 36,0 %, epoxidiertes Sojabohnenöl 1,0 bis 5,0 %, Ca / Zn Stabilisator 1,0 bis 5,0 % sowie Pigmente zu 0,5 bis 4,0 %.

[0083] The sum equals 100%.

[0084] The polymer plasticizer is based on adipic acid / sebacic acid 55.0 to 59.0 wt%, neopentyl glycol 12 to 16 wt%, butanediol 15.5 to 19.5 wt%, and isononanol 10.0 to 13.0 wt%. The total totals 100 wt%.

[0085] The hydrolysis stabilizer based on carbodiimide components is added to one of the two mixtures at a rate of 0.5 to 4%.

[0086] The Ca / Zn OnePack thermostabilizer system consists of hydrotalcite, calcium salts of fatty acids, zinc salts of fatty acids, antioxidants, and costabilizers.

[0087] Compatibility tests were then carried out, in which the samples were stored at 70 °C and 100% humidity for specified periods. Alternatively, these tests can also be carried out at 80 °C and 100% humidity.

[0088] The values ​​were compared to a control sample. The control sample for the wet value was a sample whose weight was determined one hour after removal from the humidity chamber. The dry value of the control sample was that of a sample dried for 16 hours at 70 °C and then cooled to room temperature for one hour. Sample without hydrolysis stabilizer A Sample with hydrolysis stabilizer B wet value Dry value wet value Dry value % by weight assessment % by weight % by weight assessment % by weight 1d 0,80 0 -0,19 0,76 0 -0,19 3d 1,39 0 -0,35 1,16 0 -0,26 7d 2,22 0 -0,27 1,78 0 -0,28 14d 3,08 0 -0,27 2,18 0 -0,28 28d 4,25 0 -0,36 2,46 0 -0,34 42d 5,91 0-1 grey* -0,47 3,18 0 -0,38 56d 9,23 5 grey** -0,70 3,39 0 -0,46 71d 11,85 5 grey** -1,04 4,09 0 -0,54 * slight dry coating ** distinct grey and dry coating

[0089] The values ​​in the assessment correspond to the following information: 0 = Dry grip, the film is smooth and dry (best compatibility) 1 = Dull grip, the film is still dry, a small amount of plasticizer is on the surface, resulting in a dull grip. Fingerprints are visible. 2 = Sticky grip, plasticizer has noticeably leached onto the surface, fingerprints are easily and clearly visible. 3 = Weak, dry residue; visible to the naked eye. 4 = Weak, liquid or greasy residue. 5 = Heavy, dry residue. 6 = Heavy, greasy residue.

[0090] The samples B, whose plasticizers contained the hydrolysis stabilizer according to the invention, clearly showed better results than those without hydrolysis stabilizer (A). The wet and dry values ​​were reduced.

[0091] Molar mass distributions (molecular weight distributions) were then determined from the corresponding samples using gel permeation chromatography (GPC). The results were as follows: Samples A without the hydrolysis stabilizer according to the invention: 0d 14d 28d 42d 56d 71d Mn 2200 2200 2100 2100 2000 1900 Mw 4800 4700 4500 4300 4000 3700 D 2,1 2,1 2,1 2,1 2,0 2,0 FI.% < 1000 8,5 8,6 9,3 9,7 10,8 11,5 FI.% < 500 2,4 2,3 2,6 2,6 2,9 3,0 This means: Mn = Number-mean molecular weight Mw = Weight-mean molecular mass weight D = Polydispersity (D = Mw : Mn) FI % <1000 = Percentage of molecules smaller than 1000 g / mol D = Days Samples B with hydrolysis stabilizer according to the invention yielded the following values: 0d 14d 28d 42d 56d 71d Mn 2200 2200 2200 2100 2100 2100 Mw 4900 4900 4800 4800 4600 4500 D 2,2 2,2 2,2 2,2 2,2 2,1 FI.% < 1000 9,1 8,8 9,0 9,0 10,0 9,6 FI.% < 500 2,7 2,4 2,5 2,5 2,8 2,5

[0092] The change in molecular weight is also shown graphically in the Fig. 2 The upper curve 14 shows the change in molecular weight of samples with the stabilizer according to the invention, the lower curve 16 without the stabilizer. (In the Fig. 2WM means plasticizer).

[0093] In the Figure 3 The graph shows the change over time of roofing membranes of composition Z 3, containing a hydrolysis stabilizer with a carbodiimide (curve 18) and without one (curve 20). The Young's modulus / E1-2 modulus is plotted against the storage period in weeks. The compatibility test was carried out at 70 °C and 100% relative humidity.

[0094] Further tests were conducted on compatibility tests of commercially available bitumen-compatible PVC roofing membranes, manufactured by extrusion according to the material composition described in DIN SPEC 20000-201 Table 2 - "Material designations and composition of plastics and elastomers". An adipic acid polyester was used as the polymer plasticizer, with an acrylate content of < 3% (composition Z 4): PVC 45 to 55%, chalk 4.0 to 10.0%, acrylate 0.5 to 3.0%, polymer plasticizer 27.0 to 36.0%, epoxidized soybean oil 1.0 to 5.0%, Ca / Zn stabilizer 1.0 to 5.0%, and carbon black 0.5 to 4.0%. A hydrolysis stabilizer based on carbodiimide components was added at a concentration of 0.5 to 4.0%.

[0095] The sum equals 100%.

[0096] Roofing membranes with and without a hydrolysis stabilizer containing at least one carbodiimide were used. The compatibility test was carried out at 70 °C and 100% humidity for the specified times. The evaluation of the samples corresponds to the previously provided assessment table.

[0097] Column 1 indicates the storage duration. Column 2 lists the results of the samples taken from a roofing membrane of the above composition Z 3, in which a hydrolysis stabilizer containing a carbodiimide had previously been incorporated into the polymer plasticizer. The weight fraction of the hydrolysis stabilizer was 1 wt% based on the final product.

[0098] [In column 3, a roofing membrane with composition Z 3 was tested, in which a hydrolysis stabilizer is not included. The filler chalk was replaced by kaolin. After only 21 weeks, a thick, dry coating formed on the surface of the roofing membrane.]

[0099] Column 4 lists the results obtained with a roofing membrane of composition Z 3. A hydrolysis stabilizer according to the invention was incorporated into the epoxidized soybean oil (ESO), with the proportion being 10 wt% based on the proportion of epoxidized soybean oil.

[0100] Column 5 lists the results relating to a roofing membrane of composition Z 3, in which the filler chalk was also replaced by kaolin. A hydrolysis stabilizer without carbodiimide was used.

[0101] In the last column, composition Z 3 was used with the filler chalk, but no hydrolysis stabilizer.

[0102] The assessments correspond to previously provided information: Compatibility test 70 °C, 98% humidity

[0103] Modification / Storage time in months Chalk + hydrolysis rod. Kaolin without hydrolysis rod. Chalk + ESO / hydrolysis rod. Kaolin + hydrolysis rod. Chalk without a hydrolysis rod. 17 weeks 0 0 0 0 0 18 weeks 2 2 0 0 0 19 weeks 2 3 2 1 1 20 weeks 2 5 2 2 1 21 weeks 1 5 1 3 1 22 weeks 1 1 3 3 23 weeks 1 1 3 3 24 weeks 1 1 5 4 25 weeks 0 0 26 weeks 0 0 27 weeks 0 0 28 weeks 0 0 29 weeks 0 (hardened) 0 (hardened)

[0104] The Fig. 4 The results of an outdoor weathering test can be found here. Samples were taken from extruded PVC sheets. The composition of the sheets corresponded to composition Z 3, with the exception that, as explained below, chalk was replaced by kaolin or hydrolysis stabilizers were used in some samples.

[0105] For each sample, the initial weight was first determined under laboratory conditions, i.e., at 23 °C and 50% relative humidity. After the respective weathering period, the samples were stored for one hour in laboratory conditions (30 °C / 50% relative humidity) and then dried for 16 hours at 70 °C. The weight was then determined. To obtain an accurate weight, an average of two weathered samples was calculated. The resulting weight loss was then plotted relative to the initial weight. The results are presented to Fig. 4 The abscissa represents the weathering time and the ordinate the weight loss in % compared to the initial weight.

[0106] The compositions of the samples assigned to the individual curves are as follows: Curve 22 relates to a sample of composition Z 3, in which the filler chalk was included. A hydrolysis stabilizer was not incorporated. The filler chalk was replaced by kaolin in the samples according to curve 24. A hydrolysis stabilizer was not used. Such a stabilizer was incorporated into the composition according to the samples represented by curve 26. The filler was chalk. If the filler chalk was replaced by kaolin while the hydrolysis stabilizer was still present, curve 28 resulted for the corresponding samples. An even lower weight loss was observed when the hydrolysis stabilizer according to the invention was previously incorporated into the epoxidized soybean oil, with the proportion of the hydrolysis stabilizer according to the invention being 10 wt.-% based on the proportion of epoxidized soybean oil was (curve 30).

[0107] The outdoor weathering test also demonstrates that when a hydrolysis stabilizer according to the invention, containing at least one carbodiimide, is incorporated into the initial composition of a PVC membrane containing a hydrolysis stabilizer according to the invention, the hydrolysis is significantly reduced compared to a membrane of the same composition without the hydrolysis stabilizer according to the invention.

[0108] Fig. 5The figure shows the elongation of roofing membranes of different compositions over various aging stages 1-7 according to WOM aging, where F-1 is the composition Z 3 mentioned in the patent application with 1.5% Ca / Zn stabilizer without hydrolysis stabilizer, F-2 is the composition Z 3 mentioned in the application with 3% Ca / Zn stabilizer without hydrolysis stabilizer, and F-3 is the composition Z 4 mentioned in the application with 0.5% carbon black, in particular Tinuvin XT 833 without hydrolysis stabilizer. The results show that the composition additionally equipped with Tinuvin XT 833 makes a positive contribution to hydrolysis; this composition shows the smallest decrease in elongation over aging stages 1-7.

Claims

1. Use of a composition comprising at least one carbodiimide selected from monomeric, oligomeric, and polymeric aliphatic carbodiimides, and at least one polyester plasticizer as a plasticizer for polyvinyl chloride or polyvinylchloride copolymer.

2. The use according to claim 1, characterized in that the aliphatic carbodiimide is described by the general formula where n=1 to 20 and R5 and R6 are methoxylated polyethylene glycol residues of the formula -(EO)m-OCH3 with m=1 to 20.

Images