EP2726545A1

EP2726545A1 - Surface covering comprising a citrate-based plasticizer

Info

Publication number: EP2726545A1
Application number: EP11729411.6A
Authority: EP
Inventors: Larisa ALEKSANDROVA
Original assignee: Tarkett GDL SA
Current assignee: Tarkett GDL SA
Priority date: 2011-07-01
Filing date: 2011-07-01
Publication date: 2014-05-07
Also published as: RU2014102917A; RU2578146C2; WO2013004265A1

Abstract

The present invention relates to a PVC-based composition of a surface covering layer comprising a citrate- based plasticizer, to a surface covering comprising such a layer and a method to produce such a surface covering.

Description

SURFACE COVERING COMPRISING A CITRATE-BASED PLASTICIZER

Field of the invention

[0001] The present invention relates to a composition of a surface covering layer, the composition comprising a citrate- based plasticizer and also relates to a method to produce a surface covering comprising such a layer.

Prior art and related technical background

[0002] Surface coverings, particularly PVC-based surface coverings, are widely used to decorate buildings or houses surfaces. However, the PVC-based surface coverings have the drawback of releasing VOCs (Volatile Organic Compounds) due to the presence of plasticizers, particularly phthalate plasticizers .

[0003] To address this issue, it was suggested to replace the phthalate plasticizers by alternative plasticizers. However, this solution impacts the stiffness of the surface covering while suitable stiffness is an important requirement for resilient surface coverings, especially floor coverings. Furthermore, these alternative plasticizers do no solve the problem of VOCs release from other components of PVC-based layers that constitute the surface covering.

[0004] Indeed, VOCs emissions are also due to other plasticizers such as dibenzoate plasticizers, thermal stabilizers, viscosity reducers and other additives, which are commonly used in surface covering layer compositions.

[0005] It was also suggested to use a barrier layer within the surface covering or a varnish layer, generally a polyurethane (PU) layer, applied on the top surface of the surface covering. However, even if a polyurethane layer is an efficient emission barrier, it is difficult to apply uniformly on finished products having sharp or deep surface embossing. Moreover, when the product is installed in heavy traffic areas for a long time, the barrier layer or the polyurethane layer can be worn out and emissions released again.

Aims of the invention

[0006] The present invention aims to provide a composition for a surface covering layer, a surface covering comprising such a layer, and a method to produce such a surface covering that do not have the drawbacks of the prior art.

[0007] The invention aims to provide a surface covering layer and a surface covering with suitable level of stiffness and very low VOCs emission.

Summary of the invention

[0008] The present invention relates to a PVC-based composition of a surface covering layer, said composition comprising at least one PVC resin, at least one non phthalate- based plasticizer generating VOCs and/or at least one additive generating VOCs, said composition further comprises at least one citrate-based plasticizer.

[0009] According to particular embodiments, the PVC-based composition may comprise one, or a combination, of any of the following characteristics:

the citrate-based plasticizer is selected from the group consisting in triethyl citrate (TEC) , tributyl citrate (TBC) , acetyl tributyl citrate (ATBC) , acetyl triethyl citrate (ATEC) and acetyl tri 2-ethyl-hexyl citrate (ATEHC) .

- the citrate-based plasticizer represents between 8 and 72 phr,

- the non phthalate-based plasticizer represents between 0 and 36 phr,

- the additives represent between 0 and 15 phr,

- the non phthalate-based plasticizer is selected from the group consisting in adipates, benzoates, monobenzoates and dibenzoates, trimellitates, FAME (fatty acid methyl ester) terephthalates and cyclohexanoates ,

- the additive is selected in the group consisting in liquid stabilizers, viscosity reducers, blowing agents, liquid kickers, antistatic agents and fire retardants,

the citrate-based plasticizer is acetyl tributyl citrate (ATBC) , the non phthalate-based plasticizer is diisononyl adipate (DINA) and isononyl benzoate (INB) .

[0010] The proportion of each component is given in phr, in percentage by weight of PVC .

[0011] The present invention relates to the use of the

PVC-based composition according to the invention to obtain a surface covering layer having a reduced VOCs emission.

[0012] In preferred embodiments, the surface covering layer is a support layer, a wear layer, a saturation layer, a back foam or a top foam layer of a multiple layer surface covering .

[0013] The present invention relates to the use of the

PVC-based composition according to the invention to obtain a surface covering having a reduced VOCs emission.

[0014] The present invention relates to a method to produce a surface covering comprising the steps of providing a composition according to the invention, gelling the composition at a temperature comprised between 130°C and 200°C to form a film or a layer, assembling the layer to at least another layer to form a surface covering.

[0015] According to a preferred embodiment of the method, at least another layer has a composition according to the invention .

[0016] The present invention relates to a surface covering comprising at least one layer comprising the composition according to the invention.

[0017] According to a particular embodiment, the surface covering is a floor covering. Short description of the drawings

[0018] Figure 1 represents the surface covering according to the invention.

Detailed description of the invention

[0019] The surface covering according to the invention is a multilayer PVC-based surface covering comprising at least one layer having a PVC-based composition which comprises at least one PVC resin and at least one citrate-based plasticizer.

[0020] This composition presents the advantage of getting a layer, and thus a resilient surface covering, with sustainable reduced VOCs emission (according to ISO 19000-9) even if volatile plasticizers or volatile additives generating VOCs, such as liquid stabilizers or viscosity reducers, are used to get a layer with suitable properties, such as for example stiffness .

[0021] The composition of the layer according to the invention comprises at least one non phthalate-based plasticizer, preferably a plurality of non phthalate-based plasticizers. These non phthalate-based plasticizers may, or not, be volatile, and may, or not, generate VOCs.

[0022] "Non phthalate-based plasticizers" should be understood as being plasticizers which are not ortho-phthalate esters .

[0023] The non phthalate-based plasticizers is selected from the group consisting in adipates, benzoates, monobenzoates and dibenzoates, cyclohexanoates , pyrrolidones , trimellitates , FAME (fatty acid methyl esters) terephthalates and cyclohexanoates and mixtures thereof.

[0024] The non phthalate-based plasticizers represent between 0 and 36 phr . [0025] The adipate plasticizer may be diisononyl adipate

(DINA) , dioctyl adipate (DOA) , di- (2-ethylhexyl) adipate (DEHA) or benzyl octyl adipate (BOA) .

[0026] The benzoate plasticizer may be isononyl benzoate

(INB) or isodecyl benzoate (Jayflex MB 10) .

[0027] The citrate-based plasticizer is a citrate ester of a primary alcohols comprising between two and eight carbon atoms .

[0028] The citrate-based plasticizer is selected from the group consisting in triethyl citrate (TEC) , tributyl citrate (TBC) , acetyl tributyl citrate (ATBC) , acetyl triethyl citrate (ATEC) and acetyl tri 2-ethyl-hexyl citrate (ATEHC) .

[0029] The citrate-based plasticizer represents preferably between 8 and 72 phr .

[0030] Preferably, the citrate-based plasticizer represents at least 20% wt of the total amount of plasticizers in the composition and the non phthalate-based plasticizer represents maximum 80% wt of the total amount of plasticizers in the composition.

[0031] In a preferred embodiment, the layer composition comprises between 20 and 30 phr of diisononyl adipate (DINA) and 20 to 30 phr of acetyl tributyl citrate (ATBC) .

[0032] In another preferred embodiment, the layer composition comprises between 13 and 17 phr of diisononyl adipate (DINA) , between 8 to 13 phr of acetyl tributyl citrate (ATBC) and between 13 and 17 phr of isononyl benzoate (INB) .

[0033] The composition may further comprise one or a plurality of additives, such as a liquid stabilizer, a viscosity reducer, a blowing agent, a liquid kicker, an antistatic agent, a fire retardant, or a mixture thereof. These additives may, or not, be volatile and may, or not, generate VOCs .

[0034] The additives may represent between 0 and 15 phr.

[0035] The liquid stabilizer may be for example a Ca/Zn stabilizer or a Ba/Zn stabilizer. [0036] The viscosity reducer may be for example either a linear or branched paraffin or a fatty acid methyl ester.

[0037] The blowing agent may be for example an azodicarbonamide-based agent or baking soda.

[0038] The liquid kickers may be for example a mixed metal soaps, based for example on potassium or Zinc.

[0039] The antistatic agent may be based on polyethyleneglycolether, for example Markstat from Artek Surfin Chemicals .

[0040] The layer according to the invention is obtained from the composition according to the invention by gelling the composition at a temperature of between 130°C and 200°C using either gelling drums or an oven.

[0041] The layer according to the invention may be a film or a foam.

[0042] For the foam embodiment wherein the layer composition comprises zinc oxide as blowing catalyst, the viscosity increase thus obtained can be balanced by using an adipate-based plasticizer and a citrate-based plasticizer. By doing so, the blowing ratio and the cell structure are not affected in comparison to a layer comprising phthalate plasticizers .

[0043] The layer may be used as a support layer, a wear layer, a saturation layer, a back foam or a top foam layer of a multiple layer surface covering.

[0044] Generally, the VOCs emission is defined as the sum of VVOC (Very Volatile Organic Compound), TVOC (Total Volatile Organic Compound) and SVOC (Semi Volatile Organic Compound) . It is measured at 3 days according to a test method based on ISO 16000 using microchamber carried out in Eurofins or at 28 days according to ISO 16000-9 or ISO 16000-10.

[0045] By using the composition according to the invention, the VOCs emission of the layer and of a surface covering comprising such a layer represents less then 10 yg/m³. [0046] The very low emission of VOCs of the layer comprising volatile material, or VOCs generating material, seems to be due to the use of the citrate-based plasticizer which allows to produce the surface covering layer with a particular gelled structure.

[0047] Furthermore, the use of the PVC-based composition comprising the citrate-based plasticizer allows getting a layer and a surface covering which complies with the main requirements of conventional PVC-based floor coverings comprising phthalate plasticizers, in terms of viscosity, PVC paste ageing, exudation, thermal stability, ageing ....

[0048] The surface covering according to the invention is either a mono-layer surface covering or a multiple layer surface covering (Figure 1). In a multiple layer surface covering embodiment, the surface covering may comprise one or a plurality of layers having a composition comprising citrate-based plasticizer with non phthalate-based plasticizers and/or additives which both may generate VOCs. The plurality of layers may be assembled by calendering or by spread coating layer by layer .

Examples :

Monolayer surface coverings

[0049] Comparative examples (CE1 and CE2) are monolayer surface coverings having a composition comprising a phthalate plasticizer .

[0050] The composition of CE1 and CE2 are given in table

1. Table 1: compositions of the comparative examples

[0051] The PVC is Lacovyl PB 1704H from Arkema or

Vestolit B6021 Ultra from Vestolit. The filler is Omya BL 20 from Omya. The phthalate-based plasticizer is DINP, for example Vestinol 9 from Evonik. The benzoate-based plasticizer is Vestinol INB from Evonik or Benzoflex 9-88 from Eastman. The viscosity reducer is fatty acid methyl ester, for example Byk-LP R 21151 from Byk-Chemie. The stabilizer is Lankromark LZC 393 from Akcros .

[0052] The composition of monolayer surface coverings examples according to the invention (SI to S3) are given in table 2.

Table 2: compositions of examples according to the invention

[0053] The PVC is Lacovyl PB 1704H from Arkema or

Vestolit B6021 Ultra from Vestolit. The filler is Omya BL 20 from Omya. The citrate-based plasticizer is ATBC, for example Pacizer 6412 from Patech. The adipate plasticizer is DOA, for example Plastomoll DOA from BASF, or DINA, for example Plastomoll DNA from BASF. The stabilizer is Lankromark LZC 393 from Akcros .

[0054] The VOCs emissions of the comparative samples and the samples according to the invention are given in table 3. The VOCs were measured at 3 days according to a test method based on ISO 16000 using microchamber carried out in Eurofins. The samples S3 and S4 were tested according to ISO 16000-10.

Table 3: VOCs emission of monolayer surface coverings

[0055] As expected, the layers comprising phthalate plasticizer release a high amount of VOCs, particularly TVOCs and SVOCs.

[0056] The layers having a composition comprising a citrate-based plasticizer show a reduced VOCs emission.

Multiple layer surface coverings

[0057] Comparative example CE3 is a surface covering comprising a compact layer 1 above which is laid a back foam 2, above which is laid a saturation layer 3, above which is laid a top foam layer 4, above which is laid a wear layer 5. The composition of each layers are given in table 4 in phr . The characteristics of the CE3 are given in table 5.

Table 4: Composition of the different layers of CE3.

Table 5: Characteristics of a surface covering CE3.

[0058] Comparative example CE4 is a surface covering having the same structure and layers composition as CE3, except that the plasticizer used is a non phthalate plasticizer, i.e. castor oil plasticizer, and that the wear layer further comprises 12 phr INB, in replacement of DIBP. The characteristics of the CE3 are given in table 6.

Table 6: Characteristics of a surface covering CE3

[0059] The multilayer surface covering according to the invention (S5) has the same structure as CE3 (Figure 1) but with layers having the composition of table 7 and having the characteristics of table 8.

Table 7: Composition of the different layers of S5.

Compact Back Saturation Top Wear layer foam layer foam layer

PVC 100 100 100 100 100

Filler 124 120 165 72 - citrate-based 24

49 67.9 72.4 37.5

Plasticizer

Benzoate-based 12

- - - - Plasticizer

Viscosity

13.3 - 6.58 8.33 1.81 reducer

Stabilizer - - - - 2.83

ESBO - - - - 0.9

Premix - 11.31 - 8.76 -

Plasticizer 7.27 ^— 4.62 ^—

- (OOP)

Blowing agent - 2.69 - 0.88 -

Ti02 - - - 2.54 -

ZnO - 1.35 - 0.72 Table 8: Characteristics of a surface covering

[0060] In all the examples (comparative and according to the invention) , the PVC is either Pevikon P682 from Ineos, Vinnolit EP 6953 from Vinnolit, Solvin 266 SF from Solvin, Solvin 372 NA from Solvin, EP 6602 C from Vinnolit, Vinnolit E 80 TT or Vestolit B 7021 Ultra from Vestolit, Solvin 372 NA from Solvin, Vinnolit E 68 FO from Vinnolit, LG PB 1202 or a mixture thereof .

[0061] In the comparative examples, the phthalate-based plasticizer 1 is DOP, for example Eastman DOP from Eastman. The phthalate-based plasticizer 2 is DINP for example Vestinol 9 from Evonik. The phthalate-based plasticizer 3 is DIBP for example Palatinol IC from BASF.

[0062] In the sample according to the invention, the benzoate-based plasticizer is INB (isononyl monobenzoate) for example Vestinol INB from Evonik. The citrate-based plasticizer is ATBC, for example Citrofol BII from Jungbunzlauer, or Pacizer 6412 from Patech. The castor oil is Grindsted Soft-N-Safe from Danisco .

[0063] In all the examples, the filler is calcium carbonate Mikhart 40 from Provencale. The viscosity reducer is Vegalon PB 0505 from Vega-him or Atepas 5316 from Byk-Chemie. The blowing agent is an azodicarbonamide, for example Unifoam VI 40 from Hebron. The stabilizer is Lankromark LZC 393 from Akcros. ESBO is an Epoxidized SoyBean Oil, for example Drapex 39 from Chemtura. [0064] The VOC emissions of the comparative examples and the example according to the invention were assessed according to ISO 16000-10. The results are given in table 9.

Table 9: VOCs emissions

[0065] From table 9, it appears that the comparative example CE3, having phthalate-based plasticizers , presents a high level VOCs emission. The use of a phthalate alternative, such as castor oil (CE4), reduces the VOCs emission but the level of emission is still high. However, S5 presents a low level of VOC emission. This reduction is not only due to the replacement of phthalate plasticizers with non phthalate plasticizers as CE4 presents a level only slightly lower than CE3. The use of citrate-based plasticizer has a supplementary effect as S5 comprises the same additives as CE3 and CE4, additives like the viscosity reducer Vegalon PB 0505 and the stabilizer Lankromark LZC 393 known to release VOCs. Thus, one could expect that S5 should have a VOCs emission in-between CE4 and CE3, or substantially equal to CE3 as S5 comprises a benzoate non-phtalate plasticizer which is volatile and might participate to VOCs emission. However, it should be noted that this is not the case. S5 presents an important decrease of VOCs emission. This might be due to the structure of the layer obtained from the composition comprising the citrate-based plasticizer .

Claims

1. A PVC-based composition of a surface covering layer, said composition comprising at least one PVC resin, at least one non phthalate-based plasticizer generating VOCs and/or at least one additive generating VOCs, said composition further comprising at least one citrate-based plasticizer.

2. The PVC-based composition according to claim 1, wherein the citrate-based plasticizer is selected from the group consisting in triethyl citrate (TEC) , tributyl citrate (TBC) , acetyl tributyl citrate (ATBC) , acetyl triethyl citrate (ATEC) and acetyl tri 2-ethyl-hexyl citrate (ATEHC) .

3. The PVC-based composition according to claim 1 or 2, wherein the citrate-based plasticizer represents between 8 and 72 phr .

4. The PVC-based composition according to any of the preceding claims, wherein the non phthalate-based plasticizer represents between 0 and 36 phr.

5. The PVC-based composition according to any of the preceding claims, wherein the additives represent between 0 and 15 phr.

6. The PVC-based composition according to any of the preceding claims, wherein the non phthalate-based plasticizer is selected from the group consisting in adipates, benzoates, monobenzoates and dibenzoates, trimellitates , FAME (fatty acid methyl ester) terephthalates and cyclohexanoates .

7. The PVC-based composition according to any of the preceding claims, wherein the additive is selected in the group consisting in liquid stabilizers, viscosity reducers, blowing agents, liquid kickers, antistatic agents and fire retardants.

8. The PVC-based composition according to any of the preceding claims, wherein the citrate-based plasticizer is acetyl tributyl citrate (ATBC) , the non phthalate-based plasticizer is diisononyl adipate (DINA) and isononyl benzoate (INB) .

9. Use of the PVC-based composition according to any of the claims 1 to 8 to obtain a surface covering layer having a reduced VOCs emission.

10. Use according to claim 9, wherein the layer is a support layer, a wear layer, a saturation layer, a back foam or a top foam layer of a multiple layer surface covering.

11. Use of the PVC-based composition according to any of the claims 1 to 8 to obtain a surface covering having a reduced VOCs emission.

12. A method to produce a surface covering comprising the steps of:

- providing a composition according to any of the claims 1 to 8,

- gelling said composition at a temperature comprised between 130°C and 200°C to form a film or a layer,

- assembling said layer to at least another layer to form said surface covering.

13. The method according to claim 12, wherein the at least another layer has a composition according to any of the claims 1 to 8.

14. A surface covering comprising at least one layer comprising the composition according to any of the claim 1 to 8.

15. The surface covering according to claim 14 being a floor covering.