WO2017222438A1

WO2017222438A1 - Composition and method for joining of pvc components

Info

Publication number: WO2017222438A1
Application number: PCT/SE2017/050432
Authority: WO
Inventors: Dick GUSTAFSSON; Olof HÖGSTEDT; Anders LINDéN
Original assignee: Ohla Plast & Färgteknik Ab
Priority date: 2016-06-23
Filing date: 2017-05-04
Publication date: 2017-12-28
Also published as: SE540725C2; EP3475062A4; EP3475062A1; SE1650909A1

Abstract

The invention relates to a composition for joining of polyvinylchloride (PVC) components, the composition comprising 50-95 wt% 1-butylpyrrolidin-2-one and 5–40 wt% polyvinylchloride and/or polyvinylacetate. The inventionfurther relates to a method of joining of polyvinylchloride (PVC) components using the composition.

Description

Composition and method for joining of PVC components

TECHNICAL FIELD

This invention relates to a composition for joining of polyvinylchloride (PVC) components, the composition comprising a solvent and polyvinylchloride and/or polyvinylacetate. It further relates to a method of joining of polyvinylchloride (PVC) components using the composition.

BACKGROUND ART

Joining of polyvinylchloride (PVC) components, such as floor and wall panels, are commonly carried out by using a liquid composition comprising a solvent capable of running into a joint, dissolving the PVC and allowing the PVC components to fuse together while the solvent evaporates. Such a liquid composition is often called a cold weld liquid and the corresponding joining technique is called cold welding or chemical welding. A commonly used industrial solvent for joining PVC floor panels is the organic compound tetrahydrofuran (THF). This solvent is very suitable for the purpose in question but has some serious disadvantages. THF has recently been classified as "Suspected of causing cancer". Products containing THF as solvent must thus be provided with a warning label due to the potential cancerous effect. For the one-time user the potential negative effects of THF may not be alarming, but for professionals coming into contact with the solvent every day there is a great health risk. The use of THF and similar PVC solvents available on the market requires the user to wear a mask and to work only in environments with intensive ventilation. Such requirements complicate the work for professionals. Another problem associated with THF and similar solvents is their flammability, which poses a risk of explosion and fire. Tools that may give rise to sparks can therefore not be used together with such solvents. Moreover, these solvents are subject to transportation restrictions.

Because of the toxicity and flammability of THF, some alternatives have been proposed in the past. DE4142732A1 discloses a cold weld composition using acetone as solvent. Another alternative is given in FR2804456A1 teaching that plasticized PVC panels can be joined by using water-based polyurethane glue. None of these alternatives have reached any commercial success, possibly because acetone, like THF, is toxic, flammable and evaporates readily, and it is also a poorer solvent for PVC than THF, and because polyurethane glue requires a long time to cure and has poor binding properties for PVC.

Another common method of joining PVC components is hot welding, i.e. the components are melted instead of being dissolved using a solvent. However, conventional hot melting is generally more complicated than using solvents; particular welding equipment is needed and it requires great craftsmanship to produce good looking joints. Moreover, hot welding generates corrosive and toxic gases, and it cannot be used for joining foamed PVC components.

For the above reasons, there is a need for improvements in the field of joining PVC components together.

SUMMARY OF THE INVENTION

An object of the invention is to overcome the problems outlined above; namely to provide for an efficient and qualitative way of joining PVC components without the use of toxic solvents or complicated equipment.

The invention is based on a new concept for joining; instead of using a highly volatile (toxic) solvent that can run into a joint between e.g. two PVC floor sheets and that quickly evaporates, the new concept includes a low-volatility and more viscous (non-toxic) solvent that is capable of diffusing into the components to be joined. As will be further described below, these different properties of the solvent make the conventional cold welding procedure for joining of PVC components less suitable in many applications, and an improved procedure has therefore been developed. The invention concerns a composition for joining polyvinylchloride (PVC) components, the composition comprising 50-95 wt% (weight percent) l-butylpyrrolidin-2-one and 5-40 wt% polyvinylchloride (PVC) and/or polyvinylacetate (PVA). l-butylpyrrolidin-2-one is a non-toxic and inflammable solvent that, when mixed with a certain amount of PVC and/or PVA, is very useful for joining PVC components, in particular floor panels but also e.g. pipe sections or for fitting PVC window frames. An effect of the invention is thus that PVC components can be joined together in an efficient and noncomplicated way without posing a health risk for the person carrying out the work and without the risk for explosions and fire during application or transportation. Because 1- butylpyrrolidin-2-one behaves in another way than e.g. THF, mainly due to a higher viscosity and a lower volatility, it is in some applications recommended to use a modified method for joining the components to achieve an appropriate joint (see below).

It has been found that l-butylpyrrolidin-2-one, which is a low-volatile non-toxic solvent with high polarity, provides good quality joints with surprisingly short binding time. Moreover, the low volatility provides the possibility to make the cold welding process more exact and reproducible. An excess of welding liquid/composition can be used in the process since it can be wiped off smoothly and easily without damaging the product surface, preferably by using a damp cloth.

Compared to the known solvent alternative acetone, l-butylpyrrolidin-2-one has the advantages of being less toxic, enabling the possibility of achieving improved joints (reproducible joints with better appearance), and being easier to handle (inflammable). l-butylpyrrolidin-2-one is known as such but the use of this compound in a cold weld composition for joining of PVC components is believed to be novel, l-butylpyrrolidin-2-one is also known under e.g. the following names: l-Butyl-2-pyrrolidinone, N-Butylpyrrolidone and N-Butylpyrrolidinone. The chemical formulation is C₈Hi₅NO.

The term "PVC components" refer to components, typically floor sheets/panels, which are substantially made of PVC. It is not necessary that these components are made purely of PVC. Many PVC components contain, for instance, around 10 wt% fillers, plasticizers or other additives, and around 10 wt% polyvinylacetate. The composition comprises 5-40 wt% polyvinylchloride and/or polyvinylacetate, which will mix with the PVC/PVA polymers of the PVC component and act as filler in the joint while the 1- butylpyrrolidin-2-one diffuses into the PVC components. The PVA/PVC of the composition thereby contributes to a better bond.

The concentration of PVC/PVA in the composition influences the viscosity of the composition; the higher the PVC/PVA concentration, the higher the viscosity. Different applications may require different viscosity. For instance, if there is a large gap in the joint to be sealed, and for non-horizontal applications, such as walls or inclined floors, a more viscous composition is preferable.

The composition may comprise a mix of PVC and PVA. Typically, PVC and/or PVA in powder form is mixed with the l-butylpyrrolidin-2-one. The composition may comprise various mixes of PVC and PVA, such as co-polymers etc. In a preferred embodiment of the composition, it contains only PVC (i.e. no or only small amounts of PVA). l-butylpyrrolidin-2-one differs significantly in some respects compared to conventional PVC solvents such as THF and acetone. Firstly, l-butylpyrrolidin-2-one is a rather poor solvent for PVC compared to THF. This means that more time is needed for preparing the composition than when THF is used as solvent. It also means that l-butylpyrrolidin-2-one initially may appear not to be useful when tested as a candidate for replacing THF in a composition containing dissolved PVC for joining of PVC components. Secondly, the viscosity of 1- butylpyrrolidin-2-one is much higher than that of THF so that the conventional method of applying the jointing composition to a joint and let it run into the joint can in many cases not be used. Thirdly, the volatility of l-butylpyrrolidin-2-one is much lower than that of THF, it rather migrates into the PVC components than evaporates, which extends the fusing time of the joint, which in turn calls for a modification of the conventional method for joining e.g. flooring sections/sheets. The changes to the conventional method provides for certain additional advantages, as will be described further below. In an embodiment of the invention the l-butylpyrrolidin-2-one together with the polyvinylchloride and/or polyvinylacetate constitute at least 80%, preferably at least 85%, more preferably at least 90%, of the total weight of the composition. Preferably, the composition comprises 70-85% l-butylpyrrolidin-2-one and 8-30% polyvinylchloride.

The composition is produced by adding PVC and/or PVA in powder or granulate form to liquid l-butylpyrrolidin-2-one and mixing the components to dissolve at least most of the PVC or PVA. After a few days, preferably 1-2 days, the additives are added to the mix. The composition is yet again stirred to make sure all PVC or PVA has dissolved.

In an embodiment of the invention the composition comprises 0.1-20 wt%, preferably 1-10 wt%, more preferably 2-8 wt%, additives in the form of one or several of the following compounds: stabilizers, plasticizers, pigments and/or matting agents. Such compounds are known as such. Stabilizers are added to the composition to minimize the effect of UV-radiation on the joints. UV-radiation affects the colour of the joint as it yellows the PVC or PVA. The plasticizer promotes plasticity and flexibility in the joint. The amount of additives in the composition preferably reflects the amount of additives in the PVC components that are being joined. A PVC floor component that has a high level of plasticizers is preferably joined by using a composition with similar amount of plasticizers such that the joint becomes as elastic as the floor components. Pigments are added to give the joint a desired colour, for example the same colour as the PVC components to be joined. Matting agents are added to provide the desired matting effect.

In an embodiment of the invention, the composition comprises additives in the following amounts: <5% stabilizers and/or <5% plasticizers and/or 0-10% pigments and/or 0-5% matting agents. In an embodiment of the invention, the composition comprises 2-8 wt% additives. In an embodiment of the invention the composition comprises 75-85 wt% l-butylpyrrolidin-2- one, 12-16 wt% polyvinylchloride and/or polyvinylacetate, 0-5 wt% plasticizer, 0.2-0.5 wt% stabilizer and 0-3 wt% matting agent. The invention also concerns a method for joining polyvinylchloride (PVC) components, wherein the method comprises the steps of: applying a composition of the above type onto at least a first of said components at a location intended to form part of a joint; and bringing into contact the first PVC component with a second PVC component at said location. The application of the composition onto the first component may be carried out in an indirect way; for instance, the composition may first be applied onto another surface, such as a base floor, and thereafter the component, such as a floor sheet, may be moved so as to come in contact with the composition.

The method may further comprise pressing the first and second polyvinylchloride component together at the intended joint, allowing superfluous composition to protrude from the joint when the first and second PVC component are brought into contact with each other; and allowing the first and second PVC components to fuse.

The method may also comprise wiping away protruding superfluous composition along the joint in order to achieve a smooth, non-bulging joint between the PVC components. Due to the characteristics of the composition it is easy to wipe off. It is non-sticky and does not immediately cure as compared to compositions with THF which are sticky and cure faster due to the high evaporation rate. For the same reason, compositions based on THF have a tendency to create bulges along the joint. In contrast to THF-based compositions, the present composition does not require the use of masking tape to avoid negative effects of overspill along the joint as the inventive composition can easily be wiped off with for example a damp cloth.

The composition dissolves the surface of the PVC components at the location of the joint, typically the edges of adjacent floor panels/sections/sheets or mating parts of pipe sections, and allows the components to fuse together along the contacting surfaces such as to achieve seam sealing. The fact that l-butylpyrrolidin-2-one is polar is believed to contribute to the benefits, because it is capable of migrating into the PVC which is also polar. Hence, after application, the l-butylpyrrolidin-2-one part of the composition will diffuse into the edges of the PVC components to be joined and thereby provide great adhesion effects. Because the fusion of the PVC components takes about 6-24 hours, the method preferably comprises the step of allowing the components to bond for at least 24 hours. Full or at least sufficient joint strength is normally achieved after about 3-7 days. The strength may continue to increase for some time. By using the composition disclosed herein the method allows the joint to be cold seam welded by bonding the said first and second PVC component together.

According to one aspect of the invention the composition is applied to a first surface of the first polyvinylchloride component at the location of the intended joint.

According to one aspect of the invention the composition is applied by means of an applicator provided with a nozzle through which the composition is pressed out.

The polyvinylchloride components to be joined may be floor covering sections (that in this disclosure also are referred to as floor covering sheets or panels), pipe sections, window frame sections or other PVC components than can be joined by cold welding.

The invention also concerns a use of the above composition as a joining agent for joining of a first polyvinylchloride component and a second polyvinylchloride component.

FIGURES

Figures 1-9 shows an example of a method for joining PVC floor panels using the composition. DETAILED DESCRIPTION

In the following an embodiment of the invention is shown and described, simply by way of illustration of one mode of carrying out the invention. According to one example of the invention the composition comprises:

80 wt% l-butylpyrrolidin-2-one,

14 wt% polyvinylchloride,

2.5 wt% plasticizers,

0.35 wt% stabilizers,

1.5 wt% matting agent, and

1.65 wt% pigments.

The composition is produced and mixed as described above.

This example of the composition is suitable for use in a method for joining e.g. two floor covering sections/sheets/panels. In such an example of the invention, the method comprises placing two PVC floor sections on an underlying base floor, cutting the sections, gluing them to that floor and joining them together. The PVC floor sections are initially positioned so that their side edges overlap. The method comprises providing a cut through both sections at the overlap, the cut extending along the entire length of the overlap. The cut away part of the first, upper section is removed. Thereafter, the upper PVC floor section is lifted to reveal the part cut away from the second, lower PVC section, which also is removed. A proper joint can now be formed. After applying glue onto the floor (preferably after having rolled up the floor sections and made use of masking tape, see below), the composition can be applied to the edge of an unrolled floor section. This is described in more detail below. The lifted/rolled up upper floor covering section is folded back/unrolled down into position so that the edge of the bottom floor covering section and the edge of the upper floor covering section align at the location of the intended joint. The composition is allowed to protrude from the joint between the edges. The superfluous composition is wiped away with a damp cloth so as to form a smooth joint.

An exemplified method of applying two PVC floor covering sections/panels 1, 2 onto a base floor 3 and joining the panels using a composition according to the invention will now be described in more detail with reference to figures 1-9. Figure 1 shows the two floor covering sections/floor panels 1, 2 arranged onto the floor 3. The panels 1, 2 are arranged side by side and have been cut to size and to fit to each other in a previous step (as outlined above). The panels 1, 2 are to be joined along a joint 4. A first part la, 2a, about a half, of each panel 1, 2 has been rolled up so as to expose a corresponding first part of the floor 3 and make it possible to apply a floor glue on the first part of the floor 3.

Before applying the floor glue, a masking tape 5 is applied onto the first part of the floor 3 where the joint 4 between the first parts la, 2a of panels will be positioned. Typically, the position of the joint 4 has been indicated in the floor by the previous cutting operation (where the panels 1, 2 are placed with their edges overlapping and a mat cutter has left some marks on the floor while cutting through the panels). In a next step, floor glue 6 is applied onto the first part of the floor 3 using a glue distributor 7.

In a next step, see figure 2, the masking tape 5 is removed. This way the position of the joint will be free from floor glue 6, which otherwise is likely to be pressed into the joint, mix with the joining composition and interfere with the subsequent joining of the panels 1, 2 along the joint 4.

After removing the tape 5, the first part la of the first panel 1 is unrolled and pressed onto the floor (see figures 2 and 3).

At this stage the joining composition 8 is applied from an applicator in the form of a tube 9 with a nozzle along the inside edge formed between the floor 3 and the first part la of the first panel 1, see figure 3. As indicated in figure 3, the next step is to unroll the first part 2a of the second panel 2 and press it onto the floor and towards the first part la of the first panel 1. Joining composition 8 is now present below and in the joint 4. As indicated in figure 4, superfluous joining composition 8 that has been pressed out onto the panels 1, 2 above the joint 4 can be removed using a damp cloth 10. Figure 4 also indicates that the next step is to roll up the second part lb, 2b, i.e. the remaining opposite part, of each of the panels 1, 2 to expose a second part of the floor 3. As shown in figure 5, the second parts lb, 2b are rolled-up sufficiently far to make the remaining part of the floor 3 accessible for application of floor glue 6.

Figures 5-8 shows essentially the same thing as figures 1-4 but relates to the second parts lb, 2b of the panels 1, 2. In short, the following steps are:

- applying masking tape 5 on the second part of the floor 3 along the intended position of the joint 4,

- applying floor glue 6 to the second part of the floor 3 using the glue distributor 7,

- removing the masking tape 5,

- unrolling the second part lb of the first panel 1 (or the second part 2b of the second panel 2) and pressing it into place onto the floor 3,

- applying joining composition 8 along the inside edge formed between the floor 3 and the second part lb of the first panel 1,

- unrolling the second part 2b of the second panel 2 and put it in place onto the floor 3 and along the second part lb of the first panel 1, and

- wiping away superfluous joining composition 8 using damp cloth 10.

Figure 9 shows a cross-section A-A of the floor 3, the panels 1, 2 and the joint 4 according to figure 8, i.e. before the superfluous joining composition 8 on top of the panels 1, 2 has been wiped away. Arrows in figure 9 indicate how the joining composition 8 has been pressed upwards in the joint and how the composition, with time, migrates into the floor panels 1, 2.

Figure 9 is somewhat schematic and simplified. The width of the joint 4, i.e. the distance between the panel parts lb, 2b, is somewhat exaggerated in figure 9 to more clearly show the joint. In a real case there may also be some composition 8 present on the floor 3 below the panels 1, 2 close to the joint 4.

Besides what is mentioned above, the method may include, for instance, several steps of rolling the (parts of the) panels 1, 2 or to remove air trapped between the floor 3 and the panels 1, 2. Further, it is not necessary to work only with a part of each panel; at least for shorter floor panels it is possible to in principle follow figures 1-4 but to glue an entire first panel to the floor and to join the entire first panel to a part of or an entire second panel. All the steps above can carried out in a row without any particular waiting time in-between. This means that floor gluing and joining of the floor panels can be carried out the same day. The conventional method of applying floor panels and joining them using a joining agent based on THF or another volatile solvent with low viscosity differs from the method described above. Typically, the panels are cut when placed with overlap in a similar way as mentioned above, but conventionally the panels are glued to the floor in a next step. The day after, when the floor glue has cured, masking tape is applied above and along the joint on top of the panels, the tape is cut along the joint, and the joining agent is applied into the joint using a needle nozzle. The low-viscosity joining agent can thereby run into the joint. Some widening of the joint may be needed. After allowing some time for drying/evaporation, the masking tape can be removed. The purpose of the masking tape is to protect the panels from the relatively aggressive solvent.

Besides the hazards related to the conventional joining agents, the conventional method has some disadvantages in that it is difficult to know whether sufficient amounts of the joining agent has been applied into the joint, in that it is relatively time-consuming and laborious to apply the joining agent, and in that the whole job cannot be carried out the same day (since the floor glue must be allowed to cure to avoid interfering with the joining operation).

The new method presented here is not associated with these disadvantages.

Claims

1. Composition for joining of polyvinylchloride (PVC) components, the composition comprising 50-95 wt% l-butylpyrrolidin-2-one and 5-40 wt% polyvinylchloride and/or polyvinylacetate.

2. Composition according to claim 1, wherein the l-butylpyrrolidin-2-one together with the polyvinylchloride and/or polyvinylacetate constitute at least 80%, preferably at least 85%, more preferably at least 90%, of the total weight of the composition.

3. Composition according to any one of claims 1 or 2, wherein the composition comprises 0.1-20 wt%, preferably 1-10 wt%, more preferably 2-8 wt%, additives.

4. Composition according to claim 3, wherein the additives comprises one or several of the following compounds: stabilizers, plasticizers, pigments and/or matting agents.

5. Composition according to claim 4, wherein the composition comprises additives in the following amounts: <5 wt% stabilizers and/or <5 wt% plasticizers and/or 0-10 wt% pigments and/or 0-5 wt% matting agents.

6. Composition according to any one of the above claims, wherein the composition comprises 70-85 wt% l-butylpyrrolidin-2-one and 8-30 wt% polyvinylchloride and/or polyvinylacetate.

7. Composition according to claim 3, wherein the composition comprises 2-8 wt% additives.

8. Composition according to any one of the above claims wherein the composition comprises 75-85 wt% l-butylpyrrolidin-2-one, 12-16 wt% polyvinylchloride and/or polyvinylacetate, 0-5 wt% plasticizer, 0.2-0.5 wt% stabilizer and 0-3 wt% matting agent.

9. Method for joining of a first and a second polyvinylchloride (PVC) component, wherein the method comprises the steps of:

applying a composition according to any one of claims 1-8 onto at least a first of said components at a location intended to form part of a joint; and

bringing into contact the first PVC component with a second PVC component at said location.

10. Method according to claim 9, wherein the method further comprises one or several of the following steps:

pressing said first and second polyvinylchloride component together at the intended joint;

allowing superfluous composition to protrude from the joint when the first and second PVC component are brought into contact.

11. Method according to claim 10, wherein the method further comprises the following step:

wiping away the superfluous composition protruding from the joint by wiping along the joint.

12. Method according to any one of claims 9 - 11, wherein the composition is applied by means of an applicator provided with a nozzle, through which the composition is pressed out.

13. Method according to any one of claims 9 - 12, wherein the polyvinylchloride components are floor covering sections (1, 2).

14. Method according to claim 13, wherein the method comprises the steps of:

- glueing a first floor covering section (la) to a floor (3),

- applying the composition along an edge of the first floor covering section (la),

- glueing a second floor covering section (2a) to the floor (3) along the edge of the first floor covering section (la) so as to form a joint (4) along the edge between the first and second floor sections (la, 2a).

15. Method according to claim 14, wherein the method comprises the steps of:

- applying a masking tape (5) onto the floor (3) along the intended position of the joint (4),

- applying floor glue onto the floor (3) and the masking tape (5),

- removing the masking tape (5) before applying the composition.

16. Use of the composition according to any one of claims 1-8 as a joining agent for joining of a first and a second polyvinylchloride component.