PROCESS FOR PREPARING A COARSE SURFACE TREATED FILLER MATERIAL PRODUCT

Abstract

The present invention relates to a process for preparing a surface treated filler material product, the surface treated filler material product as well as an article comprising the surface treated filler material product.

Claims

1. A process for preparing a surface treated filler material product, the process comprising at least the steps of: a) providing at least one calcium carbonate-containing filler material having i) a volume median particle size d.sub.50 value in the range from 5 to 100 μm, ii) a top cut (d.sub.98) in the range from 30 to 500 μm, and iii) a residue on a 45 μm sieve measured according to ISO 787/7 of more than 0.5 wt.-%, based on the total weight of the calcium carbonate-containing filler material, b) providing at least one surface treatment agent being in a molten or liquid state at a temperature ranging from 18 to 45° C., and c) contacting the surface of the at least one calcium carbonate-containing filler material of step a), under mixing, in one or more steps, with the at least one surface treatment agent of step b) such that a treatment layer comprising the at least one surface treatment agent and/or reaction product(s) thereof is formed on the surface of said at least one calcium carbonate-containing filler material of step a), wherein the obtained surface treated filler material product has a residue on a 45 μm sieve measured according to ISO 787/7 of more than 0.5 wt.-%, based on the total weight of the surface treated filler material product.

2. The process according to claim 1, wherein the calcium carbonate-containing filler material of step a) is selected from the group consisting of ground calcium carbonate,precipitated calcium carbonate (PCC), surface-reacted calcium carbonate (MCC) and mixtures thereof.

3. The process according to claim 1, wherein the at least one calcium carbonate-containing filler material of step a) has a) a volume median particle size d.sub.50 value in the range from 6 to 80 μm, b) a top cut (d.sub.98) in the range from 40 and 400 μm, and c) a residue on a 45 μm sieve measured according to ISO 787/7 in the range from 0.5 to 30 wt. %, based on the total weight of the calcium carbonate-containing filler material.

4. The process according to claim 1, wherein the amount of the residue on a 45 μm sieve measured according to ISO 787/7 of the at least one calcium carbonate-containing filler material of step a) and the residue on a 45 μm sieve measured according to ISO 787/7 of the surface treated filler material product differs by less than 20 wt.-%.

5. The process according to claim 1, wherein the at least one surface treatment agent of step b) has a Brookfield viscosity of ≤1 000 mPa.Math.s at 25° C.

6. The process according to claim 1, wherein the at least one surface treatment agent of step b) is a phosphoric acid ester blend of one or more phosphoric acid mono-ester and/or one or more phosphoric acid di-ester, and/or at least one mono-substituted succinic anhydride consisting of succinic anhydride mono-substituted with a group selected from a linear, branched and aliphatic group having a total amount of carbon atoms from at least C2 to C20 in the substituent or a cyclic group having a total amount of carbon atoms from at least C3 to C20 in the substituent; and/or is added in contacting step c) in a total amount of from 0.1 to 3 wt. %, based on the total dry weight of the at least one calcium carbonate-containing filler material of step a).

7. The process according to claim 1, wherein contacting step c) is carried out in that the overall energy intake by adding the at least one surface treatment agent of step b) to the at least one calcium carbonate-containing filler material of step a) is not more than 15 kWh/T.

8. The process according to claim 1, wherein contacting step c) is carried out in an Archimedean screw, a drum mixer, a pneumatic air conveyor system, a planetary mixer or a guedu mixer.

9. The process according to claim 8, wherein the Archimedean screw is operated at an angle ranging from 30 to 80°, and/or a temperature ranging from 18 to 45° C.

10. The process according to claim 8, wherein the at least one surface treatment agent of step b) is added to the at least one calcium carbonate-containing filler material of step a) in the lower 1/3 of the Archimedean screw.

11. The process according to claim 8, wherein the drum mixer, the planetary mixer or the guedu mixer has a diameter to height ratio of 1:1 to 1:5.

12. The process according to claim 1, wherein contacting step c) is carried out in that the at least one surface treatment agent of step b) is sprayed onto the at least one calcium carbonate-containing filler material of step a), and/or contacting step c) is carried out in continuous or batch mode.

13. A surface treated filler material product comprising a) at least one calcium carbonate-containing filler material having i) a volume median particle size d.sub.50 value in the range from 5 to 100 μm and ii) a top cut (d.sub.98) in the range from 30 and 500 μm, and b) a treatment layer on the surface of the at least one calcium carbonate-containing filler material comprising at least one surface treatment agent and/or reaction products thereof, wherein the surface treated filler material product comprises the treatment layer in an amount of from 0.1 to 3 wt.-%, based on the total dry weight of the at least one calcium carbonate-containing filler material, wherein the surface treated filler material product has a residue on a 45 μm sieve measured according to ISO 787/7 of more than 0.5 wt.-%, based on the total weight of the surface treated filler material product.

14. A surface treated filler material product comprising a) at least one calcium carbonate-containing filler material having i) a volume median particle size d.sub.50 value in the range from 5 to 100 μm and ii) a top cut (d.sub.98) in the range from 30 and 500 μm, and b) a treatment layer on the surface of the at least one calcium carbonate-containing filler material comprising at least one surface treatment agent and/or reaction products thereof, wherein the surface treated filler material product comprises the treatment layer in an amount of from 0.1 to 3 wt.-%, based on the total dry weight of the at least one calcium carbonate-containing filler material, wherein the surface treated filler material product has a residue on a 45 μm sieve measured according to ISO 787/7 of more than 0.5 wt.-%, based on the total weight of the surface treated filler material product; and the surface treated filler material product is obtained by a process for preparing a surface treated filler material product according to claim 1.

15. An article, comprising the surface treated filler material product according to claim 13.

16. The process according to claim 1, wherein the calcium carbonate-containing filler material of step a) is ground calcium carbonate.

17. The process according to claim 1, wherein the at least one calcium carbonate-containing filler material of step a) has a) a volume median particle size d.sub.50 value in the range from 7.5 to 50 μm, b) a top cut (d.sub.98) in the range from 50 to 250 μm, and c) a residue on a 45 μm sieve measured according to ISO 787/7 in the range from 0.75 to 25 wt.-%, based on the total weight of the calcium carbonate-containing filler material.

18. The process according to claim 1, wherein contacting step c) is carried out in that the overall energy intake by adding the at least one surface treatment agent of step b) to the at least one calcium carbonate-containing filler material of step a) is in the range from 2 to 15 kWh/T.

19. The process according to claim 1, wherein contacting step c) is carried out in in an Archimedean screw and the Archimedean screw is a screw conveyer.

20. The process according to claim 1, wherein contacting step c) is carried out in an Archimedean screw, a drum mixer, a pneumatic air conveyor system, a planetary mixer or a guedu mixer, where the at least one surface treatment agent of step b) is added to the at least one calcium carbonate-containing filler material of step a) which is loaded onto the Archimedean screw, the drum mixer, the pneumatic air conveyor system, the planetary mixer or the guedu mixer.

21. The process according to claim 8, wherein the Archimedean screw is operated at an angle ranging from 35 to 70°.

22. The article of claim 15, wherein the article is a polymeric article.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0294] FIG. 1 shows a viscosity comparison of ASA treated CaCO.sub.3 in PVC-plastisol flooring

[0295] The following examples may additionally illustrate the invention but are not meant to restrict the invention to the exemplified embodiments.

EXAMPLES

A) MEASUREMENT METHODS

[0296] The following measurement methods are used to evaluate the parameters given in the examples and claims.

[0297] Particle Size Distribution (Mass % Particles with a Diameter <X) and Weight Median Diameter (d.sub.50) of a Particulate Material

[0298] Volume determined median particle size d.sub.50(vol) and the volume determined top cut particle size d.sub.98(vol) was evaluated using a Malvern Mastersizer 2000 Laser Diffraction System (Malvern Instruments Plc., Great Britain). The d.sub.50(vol) or d.sub.98(vol) value indicates a diameter value such that 50% or 98% by volume, respectively, of the particles have a diameter of less than this value. The raw data obtained by the measurement was analyzed using the Mie theory, with a particle refractive index of 1.57 and an absorption index of 0.005. The methods and instruments are known to the skilled person and are commonly used to determine particle size distributions of fillers and pigments.

[0299] BET Specific Surface Area of a Material

[0300] Throughout the present document, the specific surface area (in m.sup.2/g) of the mineral filler is determined using the BET method (using nitrogen as adsorbing gas), which is well known to the skilled man (ISO 9277:2010). The total surface area (in m.sup.2) of the mineral filler is then obtained by multiplication of the specific surface area and the mass (in g) of the mineral filler prior to treatment.

[0301] Amount of Surface-Treatment Layer

[0302] The amount of the treatment layer on the calcium carbonate-comprising filler material is calculated theoretically from the values of the BET of the untreated calcium carbonate-containing filler material and the amount of mono-substituted succinic anhydride and the mixture of aliphatic linear or branched carboxylic acids comprising stearic acid that is used for the surface-treatment. It is assumed that 100% of the mono-substituted succinic anhydride and the mixture of aliphatic linear or branched carboxylic acids comprising stearic acid added to the calcium carbonate-containing filler material are present as surface treatment layer on the surface of the calcium carbonate-containing filler material.

[0303] Tensile Tests

[0304] The specimens were Typ 1B according to ISO 3167, and tensile tests were performed according to ISO 527, on 15 cm “dog bone shaped specimen”. E-modulus and tensile strength, elongation at break tests were performed on a Zwick Roell, Type Z020 equipment according to ISO 527-3.

[0305] Melt Flow Index

[0306] Melt flow index was determined according to ISO 1133 (ASTM D1238), at 190° C. and a load of 5 kg or 10 kg, respectively, on a Ceast machine (IT), Type “Melt flow modular line”.

B) EXAMPLES

a) Example 1

[0307] This example relates to the preparation of a surface treated filler material product in accordance of the present invention.

[0308] For the preparation of the surface treated filler material product, Urgonian limestone was dry ground in a horizontal ball mill. The obtained calcium carbonate-containing filler featured a d.sub.50 of approximately 6.6 μm, a top cut d.sub.98 of 49.3 μm, residue on 45 μm sieve of 1,4 wt.-%, and a specific surface area BET of 1.1 m.sup.2/g and a residual moisture content of 0.2 wt.-%.

[0309] The obtained spray dried calcium carbonate-containing filler material was further treated as outlined in the following tests.

[0310] Test 1 (Reference Treatment)

[0311] The spray dried calcium carbonate-containing filler mineral was continuously fed at a rate of 200 kg/h in a pin mill and treated with liquid alkenylsuccinic anhydride (“ASA”, Hydrores AS 1000, CAS number 68784-12-3, commercially available from Kemira Oyj, Vaasa, Finnland) fed at a rate of 6 kg/h in a Contraplex 250 CW pin mill (with disc diameter of 250mm, at a rotational speed of 3 000 revolutions per minute of the door and at a rotational speed of the housing of 6 000 revolutions per minute, and containing 120 pins in the door and 120 pins in the housing one three rows) made by the company HOSOKAWA ALPINE™ (Augsburg, Del.) and at 100° C. in order to achieve a surface treatment of 0.3 wt.-%.

[0312] Test 2 (Treatment According to the Present Invention)

[0313] The spray dried calcium carbonate-containing filler mineral was continuously fed at a rate of 750 kg/h on a conveying screw of 4 m length and an inclination of 30° via a horizontal conveying screw having a length of 2.8 m. The liquid alkenylsuccinic anhydride (“ASA”, Hydrores AS 1000, CAS number 68784-12-3, commercially available from Kemira Oyj, Vaasa, Finnland) was fed at a rate of 22.5 kg/h onto the horizontal conveying screw at ambient temperature of about 25° C. At the end of the inclined conveying screw, the surface treated calcium carbonate-containing filler material product with a surface treatment of 0.3 wt.-% was allowed to drop in a silo.

[0314] The size distribution of particles of the feed of tests 1 and 2 were analyzed with Mastersizer 2000 from Malvern Instruments (UK) for the determination of the mean particle size distribution d.sub.50 and top cut d.sub.98, and the sieve residue on a 45 μm sieve measured according to ISO 787/7, before and after the treatment according to the reference treatment with a pin mill and according to the present invention, and results are shown in table 1.

TABLE-US-00001 TABLE 1 Feed (initital spray dried calcium carbonate-containing Feed Feed filler mineral) (Test 1) (Test 2) 0.3% ASA treated No Yes Yes Treatment method — Pin mill Conveyor screw d.sub.98 49.3 μm 28.0 μm 52.9 μm d.sub.50  6.6 μm  7.8 μm 6.97 μm Residue 45 μm 1387 3 1474 sieve mg/100 g

[0315] As can be readily seen from table 1, during surface treatment in the pin mill (test 1), the particle size distribution of the feed of calcium carbonate-containing mineral filler is significantly affected. The top cut value d.sub.98 is almost half of it's initial value, and the median particle size d.sub.50 is increased by about 20%, and almost no sieve residue at 45 μm. Compared to the surface treated material according to the present invention (test 2), wherein the median particle size d.sub.50 only increased by about 5%, and top cut value slightly increase which might be due to some minor aggregates, also the sieve residue is close to the value of the untreated feed material.

[0316] These results show that the surface treatment method according to the present invention does not only consume less energy for its preparation but also does not incure any significant changes of the physical properties of the feed material, and that therefore the surface treated calcium carbonate-containing mineral filler material product, is almost equivalent to the feed material, with the exception that it is surface treated.

b) Example 2

[0317] The surface treated calcium carbonate-containing filler material products of test 1 of example 1, i.e. sample 1 was prepared according to the reference treatment, and of test 2 of example 1, i.e. sample 2 was prepared according to the process of the present invention, were used.

[0318] Sample 1 and Sample 2 were incorporated into a PVC-plastisol flooring composition and viscosity measurements were carried out. In addition, non surface treated calcium carbonate-containing filler material (feed) without surface treating agent (sample 3) and non surface treated calcium carbonate-containing filler material (feed) with surface treating agent added separately (sample 4) to the PVC-plastisol flooring composition were added. Viscosities were measured on an Anton Paar (CH), Type MCR 300 rheometer, according to the CC27 method system, using a cylindric system and spindle with 27 mm diameter, 1 mm gap between the spindle and the cylinder, at 23° C., with a 5 min. pre-tempering of the paste at shear rate of 10 sec.sup.−1, and 1.) upward slope of 0-30 sec.sup.−1 within 120 sec, 2.) constant for 60 sec at 30 sec.sup.−1, and 3.) a downward slope of 30-0 sec.sup.−1 within 120 sec. Data analysis is based on the values of the downward slope of part 3 of the measurement. The composition of the PVC-plastisol floorings are set out in table 2.

TABLE-US-00002 TABLE 2 CaCO.sub.3 + CaCO.sub.3 + 0.3 wt.-% 0.3 wt.-% CaCO.sub.3(Feed) CaCO.sub.3(Feed) ASA (sample 1 - ASA (sample 2 - untreated untreated reference) inventive) (sample 3) (sample 4) 150 phr 150 phr 150 phr 150 phr E-PVC 100 phr 100 phr 100 phr 100 phr (Lacovyl PB 1301) DINP*  75 phr  75 phr  75 phr  75 phr ASA — — — 0.3 wt.-% into formulation *Diisononyl Phthalate, CAS 68515-48-0, added as plasticizer

[0319] FIG. 1 shows the influence of the particle size and surface treating agent on the viscosity of the PVC plastisol flooring composition. The surface treated filler material product obtained by pin mill coating (reference) shows an increase of viscosity as compared to the non-treated CaCO.sub.3. Viscosity is improved when alkenylsuccinic anhydride is added directly to the PVC-plastisol flooring composition. The best viscosity results are obtained when a surface treated filler material product prepared according to the present invention is added to the PVC-plastisol flooring composition.

c) Example 3

[0320] A surface treated calcium carbonate-containing filler material product was prepared according to test 2 of example 1 of the present invention, wherein the surface treatment with ASA was 0.5 wt.-%. The preparation of the samples in S-PVC is set out in table 3 below.

TABLE-US-00003 TABLE 3 E1 E2 E3 E4 Samples (Reference) (Inventive) (Inventive) (Inventive) S-PVC (k value 66, 100 phr 100 phr 100 phr 100 phr Inovyn) DINP* 30 phr 30 phr 30 phr 30 phr Ca/Zn stabilizer (CZ 2.5 phr 2.5 phr 2.5 phr 2.5 phr 2913) CaCO.sub.3 (untreated) 170 phr CaCO.sub.3 (0.5 wt.-% 170 phr 180 phr 190 phr ASA surface treated) *Diisononyl Phthalate, CAS 68515-48-0, added as plasticizer

[0321] E1 is a reference material prepared with uncoated calcium carbonate-containing filler material. E2 to E4 are inventive materials prepared with a surface coated calcium carbonate-containing filler material product according to the present invention, wherein the surface coated calcium carbonate-containing filler material product was added in different amounts.

[0322] The sample materials were dryblend mixed in a Thermomix (from Fa. Vorwerk, Germany) for 120 seconds at 120° C. and 6000-7000 rpm before two-roll mill processing at 170° C. Specimens were cut from pressed sheets performed on a hydraulic press from Collin, type P300P, for conducting tensile tests. Hydraulic pressing was performed on a 2 mm thick metallic frame, 17 cm×17 cm, with 200 g of roll milled material. Pressing was performed at 170° C., at 200 bar and for 2 min. Thereafter the press was let to cool down at 15° C. (water cooling) while pressure was maintained at 200 bar. The test results of the samples in S-PVC are set out in table 4 below.

TABLE-US-00004 TABLE 4 E1 E2 E3 E4 Samples (reference) (Inventive) (Inventive) (Inventive) E-modulus [N/mm.sup.2] 766 615 781 626 Tensile strength [N/mm.sup.2] 9.4 8.6 9.0 7.6 Elongation at break [%] 93 104 100 106

[0323] The cut specimens for tensile testings were made by a cutting device from Fa. Hans Naef AG (CH). The specimens were Typ 1B according to ISO 3167, and tensile tests were performed according to ISO 527, on 15 cm “dog bone shaped specimen”. E-modulus and tensile strength, elongation at break tests were performed on a Zwick Roell, Type Z020 equipment according to ISO 527-3.

[0324] Inventive examples E2 to E4 show an overall increased elongation at break behavior over the reference sample, whereas the E-modulus and Tensile strength show a maximum in inventive example E3.

d) Example 4

[0325] A surface treated calcium carbonate-containing filler material product was prepared according to test 2 of example 1 of the present invention, wherein the surface treatment with ASA was 0.5 wt.-%. The preparation of the samples in polyolefins is set out in table 5 below.

TABLE-US-00005 TABLE 5 E5 E6 E7 E8 E9 (reference) (Inventive) (reference) (Inventive) (Inventive) Samples (1) (1) (2) (2) (2) LLDPE* 15 wt.-% 15 wt.-% 7 wt.-% 7 wt.-% 6 wt.-% CaCO3 85 wt.-% 75 wt.-% (untreated) CaCO3 (0.5 85 wt.-% 75 wt.-% 80 wt.-% wt.-% ASA) Elastomer ** 14 wt.-% 14 wt.-% 11 wt.-% Mineral oil .sup.# 4 wt.-% 4 wt.-% 3 wt.-% *LLDPE (ExxonMobile, LLDPE LL 6101, MFI = 20), ** Elastomer (Dow, Engage 7270, MFI = 0.8), .sup.# Mineral oil (Paraffin oil, VWR Chemicals, viscosity: 69 cSt); (1) PE compounding application, (2) PE heavy layer application

[0326] The sample materials were compounded and melt flow index was determined on a Ceast machine (IT), Type “Melt flow modular line”, according to ISO 1133 (ASTM D1238), at 190° C. and a load of 5 kg or 10 kg respectively. The test results of the samples in polyolefins are set out in table 6 below.

TABLE-US-00006 TABLE 6 E5 E6 E7 E8 E9 (reference) (Inventive) (reference) (Inventive) (Inventive) MFI (190° C./10 kg) 1.2 2.8 [g/10 min] MFI (190° C./5 kg) 4.3 6.6 3.1 [g/10 min]

[0327] The melt flow index of the surface treated calcium carbonate-containing mineral filler material product, shows improved or almost similar meltflow index at same or increased filler level.

e) Example 5

[0328] A surface treated calcium carbonate-containing filler material product was prepared according to test 2 of example 1 of the present invention, wherein the surface treatment with ASA was 0.5 wt.-%. The preparation of the samples in S-PVC is set out in table 7 below.

TABLE-US-00007 TABLE 7 E10 E11 Samples (Reference) (Inventive) S-PVC (k value 66, 100 phr 100 phr Inovyn) Ca/Zn stabilizer (CZ 3.5 phr 3.5 phr 2913) CaCO.sub.3 (untreated) 60 phr 0 CaCO.sub.3 (0.5 wt.-% 0 60 phr ASA surface treated)

[0329] The sample materials were dryblend mixed in a Thermomix (from Fa. Vorwerk, Germany) for 120 seconds at 120° C. and 6000-7000 rpm before two-roll mill processing at 170° C. The dryblend mix was further processed on a Haake™ Rheomix OS twin screw kneader (Thermo Fisher) in order to evaluate the gelation behavior of the dry blend. The kneading conditions were 170° C. at 30 rpm on two counter rotating delta rotors. The dryblend amount in the kneading chamber was 85 g. Gelation, sometimes also called plastification, is generally understood as the process in which the lubricant, often included in the stabilizers, diffuses into the particles of PVC resin during processing.

TABLE-US-00008 Sample Gelation time E10 (Reference) 96 sec E11 (Inventive) 66 sec

[0330] ASA treatment shows a clear reduction in gelation time. Which means that the production output on the extrusion line can be increased by using ASA treated CaCO.sub.3.