CA1116769A - Caco.sub.3 filled siding with improved weathering - Google Patents
Caco.sub.3 filled siding with improved weatheringInfo
- Publication number
- CA1116769A CA1116769A CA000298728A CA298728A CA1116769A CA 1116769 A CA1116769 A CA 1116769A CA 000298728 A CA000298728 A CA 000298728A CA 298728 A CA298728 A CA 298728A CA 1116769 A CA1116769 A CA 1116769A
- Authority
- CA
- Canada
- Prior art keywords
- calcium carbonate
- pvc
- siding
- coated
- lbs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K9/00—Use of pretreated ingredients
- C08K9/04—Ingredients treated with organic substances
Abstract
CaCO3 FILLED SIDING WITH IMPROVED WEATHERING
Abstract of the Disclosure White PVC composition and building panel made of such Composition. The PVC composition includes between about 2 and about 50 wt% based on PVC of finely divided amorphous calcium carbonate filler, the particles of which are coated with calcium salt of a fatty acid such as stearic acid and an effective amount of a UV absorber.
TiO2 is usually present as a pigment and is also preferably present as the W absorber.
Abstract of the Disclosure White PVC composition and building panel made of such Composition. The PVC composition includes between about 2 and about 50 wt% based on PVC of finely divided amorphous calcium carbonate filler, the particles of which are coated with calcium salt of a fatty acid such as stearic acid and an effective amount of a UV absorber.
TiO2 is usually present as a pigment and is also preferably present as the W absorber.
Description
BACKGROUND OF THE INVENTION
Calcium carbonate is a commonly used filler for rigid polyviryl chloride (PVC) compounds used in making various products such as pipes. While not commonly used, 5calcium carbonate has also been used as a filler in PVC
siding.
PVC products intended for exterior use require protection from ultraviolet (UV) radiation to avoid excessive fading and chal~ing. While some products are 10made with a separate outer layer or protective coating adapted to provide such protection, it is erequently desired to provide such protection against weathering by incorporating one or more UV absorbers in the PVC
composition itself.
15Unfortunately UV stabilized, while PVC products such as those used for building panels are subject to some yellowing of the product; particularly during the initial stages of exposure. Such yellowing can be reduced by incorporating additional amounts o UV absorber. UV
20absorbers are, however, expensive and it is desirable to use a minimum amount of UV absorber consistent with desired resistance to weathering.
SUMMAR P THE INVENTION
25It is an object of the invention to provide an improved PVC composition suitable for making white, rigid PVC products such as building panels.
It has now been found that calcium carbonate may be used successfully as a filler in white P~C compositions, including building panels such as siding, provided finely ground amorphous calcium carbonate is used and the individual particles of calcium carbonate are-coated with calcium of a higher fatty acid. More specifically, the invention contemplates a white PVC composition comprising:
a) PVC;
b) between about 2 and about 50 pounds per hundred pounds of PVC resin (PHR) of finely divided amorphous calcium carbonate filler having an average particle size between about 0.1 and about 1.0 micron with at least about 90% of such calcium carbonate particles used having a maximum ~particle size of not more than about 2 microns, the individual particles of such filler being coated with calcium salt of a higher fatty acid; and c) an effective amount of a UV absorber.
In a preferred embodiment, stearic acid is utilized so that the resulting calcium carbonate filler particles are coated with calcium stearate. Preferred embodiments also include the use of TiO2 as both a pigment and as a UV
absorber. The invention also contemplates rigid building panels such as PVC siding comprising the composition of the invention.
DETAIL~D DESCRIPTIQN OF THE INVENTION
As mentioned above, the composition of the invention comprises white PVC, finely divided amorphous calcium carbonate coated with calcium salt of a higher fatty acid and a W absorber.
PVC suitable for use in compositions and rigid building panels of the invention includes any of the conventional PVC materials generally considered suitable for use in the manufacture of rigid PVC products. These include, for instance, materials such as polyvinyl chloride itself, poly vinylidene chloride, copolymers thereof, post chlorinated polyvinyl chlorides, mixtures of polyvinyl chlorides with chlorinated polyethylenes or acrylonitriles, butadiene/styre-ne copolymers, etc. PVC
material for use in the invention usually has a weight average molecùlar weight between about 30,000 and about 200,000 more usually between about 50,000 and about 100, 000 .
It is generally preferred that the PVC used in the products of the invention be at least about 80 wt~ vinyl chloride polymer with from 0 to about 20 wt% of one or more of the other monomers or copolymers mentioned being present.
Suitable coated calcium carbonate filler is based upon finely divided amorphous calcium carbonate such as chalk. The use of more crystalline forms of calcium carbonate such as marble does not appear to provide the unexpected advantages found when coated particles of amorphous calcium carbonate are used. Finely ground amorphous calcium carbonate having an average particle diameter between about 0.1 and about 1.0 microns with a maximum particle size for at least about 90~ of the particles of not more than about 2 microns is required.
The individual particles of amorphous calcium carbonate are coated with the calcium salt of a higher fatty acid, i.e., a fatty acid having at least 12 carbon atoms in the molecule. Stearic acid is a preferred fatty acid for use in preparing the product of the invention.
The calcium salt coating may be obtained in a conventional manner by mixing the fatty acid with the calcium carbonate particles, preferably at temperatures between about 60 and about 200C so that the fatty acid reacts with the surface of the calcium carbonate to form on the carbonate particles an adherent coating of calcium salt. Such coating substantially covers the individual particles, although it should be understood that in some instances some of the fatty acid may also be present on the surface of the carbonate particles. Coated calcium carbonate ~iller used in products of the invention is well known for other uses such as in the manufacture of PVC products which do not contain UV absorbers. Such filler is available, for instance, under the trade name Omyalite 90T. Coated calcium carbonate filler as d scribed herein is used in products of the invention in amounts broadly ranging between about 2 an~ about 50 PHR. For exterior applications such as siding, where weatherability is a problem, amounts between about 5 and about 35 PHR, more especially between about 5 and about 12 PHR are preferred.
It is preferred that the total of calcium salt of higher fatty acid present as coating on the calcium carbonate particles and any unreacted higher fatty acid be present in products of the invention in amounts not exceeding about 3 P~R. Excessive amounts o higher fatty acid or salts thereof can result in overlubrication, whereby impact, strength and homogeniety o t~se finished product is adversely affected.
As mentioned above, PVC products such as siding, intended for exterior use require the incorporation of W
absorbers in the PVC composition if excessive fading or chalking due to weathering is to be avoided. UV absorbers may be any of the materials commonly sold for such purpose, including for instance benzotriazoles, ben~ophenoner and substituted acrylonitriles. Alternatively, additional TiO2 may be incorporat~ed into the PVC composition so that the Tio2 functions as a UV a~\sorber as well as a ~hite pigment. TiO2 when used as a pigment is normally used in amounts between about 1 and about 3 PHR. When additional TiO2 is incorporated for the purpose of providing UV
protection as well as normal pigmentation, the amount of TiO2 used is normally between about 5 and about 2S PHR.
Other UV absorbers, when used, are normally used in amounts between about 0.1 and about 5 PHR.
The titanium dioxide used as a pigment or as a UV
absorber in the products of the invention may be any titanium dioxide normally used as white pigme~station in rigid PVC products. The rutile form of TiO2 is considered most satisactory since its relatively higher refractive index and reflectivity and opacity is desirable.
However, for economy it is possible to use up to about 40 wt% based on TiO2 of the anatase form. Excessive amounts of anatase are undesirable because of the recognized in~eriority of anatase relative to rutile in regard to weathering characteristics of the finished product. This is especially significant in the production of PVC building panels, such as siding, intended for exterior use.
In addition to the basic ingredients of PVC, coated calcium carbonate particles and TiO2 described above, the products of the invention may contain other ingredients normally used in rigid PVC products such as stabilizers, processing aids, lubricants, impact modifiers, additional fillers, etc. Such other ingredients, when used, frequently are used in amounts totaling between about lO
and about 40 PHR. Conventional plasticizers such as dioctyl phthalate, dihexyl phthalate, phthalate esters, etc. may also be included in the! products of the invention.
Depending on the particular physical properties desired, ot~er ingredients used, etc., plasticizer may be included in compositions of the invention in amounts up to about 30 PHR.
Rigid PVC compositions of the invention may be manufactured in any suitable conventional manner, such as to powder or pellet extrusion, calendering, thermoforming, etc., it being understood that suitable methods for manufacturing rigid PVC products such as pipes, siding, etc. are well known in the art and do not constitute a part of this invention~ While manufacturing methods are not a :, .
7~
part of the invention, it should also be understood that the particular manufacturing technique selected may effect the desirable formulation of the product of the invention within the broad limits given above.
The followiny examples illustrate preferred embodiments and advantages of the invention, but are not intended to limit the scope of the invention. In exàmples, yellowing of the various samples tested was measured after six months exposure. This particular time interval was selected because white PVC siding pigmented with TiO2 characteristically yellows to the maximum degree in about this time at the location where these tests were carried out. Following initial yellowing, chalking usually occurs followed by further yellowing. The yellowing is normally at its worst, i.e. most yellow, about 3-9 months after initial exposure depending upon the climatic conditions to which the siding is exposed.
EXAMPLE I
To evaluate the effectiveness of various forms of calcium carbonate filler in reducing yellowing of white PVC
siding, a number of siding samples were prepared from filled compounds formulated as described herein and exposed in a southerly direction at an angle of about 45 in northern New Jersey for a period of six months. The various calc um carbonate filled PVC compounds lrom which the siding panels tested were produced were formulated and extruded in a conventional manner using screw extruders and the siding panels were produced by conventional extrusion 6~3 techniquesO The method of manufacture was in all cases substantially identical. The only difference in the various panels tested was the type of calcium carbonate filler used. For these tests the formulation used comprised, in addition to the calcium carbonate filler, the following ingredients:
Ingredient Parts by Weight PVC Homopolymer (I.V. 0.90) lO0 Tin Stabilizer 1.6 Acrylic Impact Modifier 7.0 Process Aid 1.5 ~ax 0.95 Calcium stearate 2.00 TiO2 (semi-rutile) 14.00 .
Calcium carbonate particles were in each instance used in the formulation testedl in an amount of lO PHR.
Calcium carbonate particles used in forming siding samples A-F, for which test results are reported below, were as follows:
Sample A was a control sample in which no calcium carbonate filler was used.
Sample B used calcium carbonate particles wet ground to an average particle size of 2.5 microns from amorphous chalk with the maximum particle size being about lO microns (i.e. at least 90% of the particles were no larger than lO microns in size). These calcium carbonate particles were coated with calcium stearate.
79~
Sample C incorporated calcium carbonate particles obtained by wet grinding marble to an average particle si~è
of 0.7 microns with a maximum particle size of 2 microns.
These particles also were coated with calcium stearate.
Sample D incorporated amorphous calcium carbonate particles wet ground to an average particles size of 0.7 microns with a maximum particle size of about 2 microns.
These particles were coated with calcium stearate.
` Sample E incorporated calcium carbonate particles ground from a relatively crystalline calcium carbonate to an average particle size of 0.7 microns with a maximum particle diameter of about 2 microns. These particles were not coated with calcium stearate.
Sample F incorporated c:alcium carbonate particles formed by precipitation and having particle si%e diameters between 0.1 and 0.35 micron. These particles were not coated with calcium stearate.
Table I below shows the results obtained when the samples of siding described above were first exposed immediately after manufacture and after six months' exposure under the conditions described above. In Table I, values are reported for both "Hunter Color Ll' (a conventional test in which the L value measures lightness with an L value of 100 being perfectly white) and the "b"
value (another conventional test in which the b value indicates degree of yellowing with increasing yellowing causing positive changes in b value).
_g_ a~
~1 ~ . .
~ o o o ~q ~ I~ ~r o a~ cn ~1 ~ ~ ~
~ o o o o e .,, ~
~ u~ ~1 ~ ~ o ~ a~ ~
U~ ~ ~ I~ ~ _, ~ O O O
~ a) ~ ~ U~
3 u~ ~1 ~ ~ o t: a~ ~n O
U~
aJ .a I - o ~ ~ o u ~ ,.,N N ~ ~
m .~ - ~
C~ ~3 C:: ~i O
lQ _~
o e .,, ~
~ u~ ~1 ~ ~ o O ~ ,O~ ~
C~ ~ O _l O
~ ~ ~ .
U~ _~ ~D ~
cn b'~
o a a 4 U~
.IJ O ~1 0 ~ x ~ x ~l H ~ C:~
From Table I it can be seen that the control sample A containing no calcium carbonate filler has a delta b (representing the difference between the b value measured immediately after manufacture and that measured after six months' exposure) of 0.7. By contrast sample D, the only sample tested which was formulated in accordance ~ith the invention, had a delta b after six months' of only 0.1.
Other samples tested, none of which were formulated in accordance with the invention, had delta b values after six months ranging from 0.6 to 0.9. It is thus apparent that both the uncoated calcium carbonate filler and the coated calcium carbonate filler in which crystalline calcium carbonate was used were of essentially no help in improving the yellowing characteristics of the finished siding. Even the coated amorphous calcium carbonate having an average particle size of 2.5 microns (~3ample B) was unsatisfactory in this respect. Only the siding sample formulated in accordance with the invention, i.e., containing very fine ground amorphous calcium carbonate particles coated with calcium stearate, provided this unexpected advantage.
EXAMPLE II
This example illustrates the effectiveness of the finely divided amorphous calcium carbonate ~iller required by the invention in reducing yellowing of white PVC siding exposed in a southerly direction at an angle c~f about 45 degrees in Arizona for a period of nine months.
s~
The siding panels tested were produced in the same manner described above in Example I. The control sample was produced from the same formulation used in producing the - control Sample A of Example I, while the remaining samples tested in this example were produced using various amounts of the same coated calcium carbonate particles utilized in Sample D of Example I. The composition of the samples tested in this example and changes in b values of the samples tested after six and nine months are reported in Table II below.
~L~
- CCl~
a~ ~ o o o o . ~, JJ
aJ a~
~U
~a ~o .,, U~ o o o . ~ . .
H C ~11~ t~
~ ~a ~ ~ . ~ .
O ~ ~ o ~ a ~ C~ ~
C) aJ
Eit~ ~ H ~) 1~1 U~
t~
It can be seen that Examples H, I and J which contain varying amounts of coated calcium carbonate filler according to the invention exhibit substantially less ~ difference in b values than did the control Sample G which did not contain the coated calcium carbonate filler. The substantially larger differences in b value in Example II
versus those reported in Example I were due to the fact that the test panels for Example II were exposed in Arizona rather than New Jersey and were therefore subjected to considerably greater amounts of solar radiation.
EXAMPLE III
This example demonstrates the usefulness of the invention when chlorinated polyethylene (CPE) impact modifier is used. Such impact modifier is known to cause yellowing of PVC products to the extent that more expensive ac~rylic impact modifiers have in the past normally been used for PVC products intended for exterior use. As shown in ~he example, white PVC products of the invention may include ingredients such as CPE which normally promote yellowness upon prolonged exposure of the product to the sun. For this evaluation four compounds identified below as compounds K,L, M & N were tested according to the procedure outlined in Example I, Compounds K and M had the following compositions.
Compound K Compound Ingredient (PHR) (PHR) PVC Homopolymer (0.9 I.V.) 100 100 Tin Stabilizer 1.6 1.6 CPE 10.0 15.0 Process Aids 1.5 1.5 Calcium Stearate 2.0 2.0 Wax 0.95 0 95 i2 7.0 7 0 10Compound L was identical witb compound K except for the addition of 20 PHR of the coated calcium carbonate of Sample D of Example I and compound N was identical with compound M except for the addit:ion of 35 PHR of the coated calcium carbonate of Sample D of Example I. When formed 15into test panels and evaluat~ed for changes in b value according to procedures outlines in Example I, the following results were obtained.
Sample: R L M N
Difference in value after 6 2.2 1.11 2.58 1.24 mos. exposure
Calcium carbonate is a commonly used filler for rigid polyviryl chloride (PVC) compounds used in making various products such as pipes. While not commonly used, 5calcium carbonate has also been used as a filler in PVC
siding.
PVC products intended for exterior use require protection from ultraviolet (UV) radiation to avoid excessive fading and chal~ing. While some products are 10made with a separate outer layer or protective coating adapted to provide such protection, it is erequently desired to provide such protection against weathering by incorporating one or more UV absorbers in the PVC
composition itself.
15Unfortunately UV stabilized, while PVC products such as those used for building panels are subject to some yellowing of the product; particularly during the initial stages of exposure. Such yellowing can be reduced by incorporating additional amounts o UV absorber. UV
20absorbers are, however, expensive and it is desirable to use a minimum amount of UV absorber consistent with desired resistance to weathering.
SUMMAR P THE INVENTION
25It is an object of the invention to provide an improved PVC composition suitable for making white, rigid PVC products such as building panels.
It has now been found that calcium carbonate may be used successfully as a filler in white P~C compositions, including building panels such as siding, provided finely ground amorphous calcium carbonate is used and the individual particles of calcium carbonate are-coated with calcium of a higher fatty acid. More specifically, the invention contemplates a white PVC composition comprising:
a) PVC;
b) between about 2 and about 50 pounds per hundred pounds of PVC resin (PHR) of finely divided amorphous calcium carbonate filler having an average particle size between about 0.1 and about 1.0 micron with at least about 90% of such calcium carbonate particles used having a maximum ~particle size of not more than about 2 microns, the individual particles of such filler being coated with calcium salt of a higher fatty acid; and c) an effective amount of a UV absorber.
In a preferred embodiment, stearic acid is utilized so that the resulting calcium carbonate filler particles are coated with calcium stearate. Preferred embodiments also include the use of TiO2 as both a pigment and as a UV
absorber. The invention also contemplates rigid building panels such as PVC siding comprising the composition of the invention.
DETAIL~D DESCRIPTIQN OF THE INVENTION
As mentioned above, the composition of the invention comprises white PVC, finely divided amorphous calcium carbonate coated with calcium salt of a higher fatty acid and a W absorber.
PVC suitable for use in compositions and rigid building panels of the invention includes any of the conventional PVC materials generally considered suitable for use in the manufacture of rigid PVC products. These include, for instance, materials such as polyvinyl chloride itself, poly vinylidene chloride, copolymers thereof, post chlorinated polyvinyl chlorides, mixtures of polyvinyl chlorides with chlorinated polyethylenes or acrylonitriles, butadiene/styre-ne copolymers, etc. PVC
material for use in the invention usually has a weight average molecùlar weight between about 30,000 and about 200,000 more usually between about 50,000 and about 100, 000 .
It is generally preferred that the PVC used in the products of the invention be at least about 80 wt~ vinyl chloride polymer with from 0 to about 20 wt% of one or more of the other monomers or copolymers mentioned being present.
Suitable coated calcium carbonate filler is based upon finely divided amorphous calcium carbonate such as chalk. The use of more crystalline forms of calcium carbonate such as marble does not appear to provide the unexpected advantages found when coated particles of amorphous calcium carbonate are used. Finely ground amorphous calcium carbonate having an average particle diameter between about 0.1 and about 1.0 microns with a maximum particle size for at least about 90~ of the particles of not more than about 2 microns is required.
The individual particles of amorphous calcium carbonate are coated with the calcium salt of a higher fatty acid, i.e., a fatty acid having at least 12 carbon atoms in the molecule. Stearic acid is a preferred fatty acid for use in preparing the product of the invention.
The calcium salt coating may be obtained in a conventional manner by mixing the fatty acid with the calcium carbonate particles, preferably at temperatures between about 60 and about 200C so that the fatty acid reacts with the surface of the calcium carbonate to form on the carbonate particles an adherent coating of calcium salt. Such coating substantially covers the individual particles, although it should be understood that in some instances some of the fatty acid may also be present on the surface of the carbonate particles. Coated calcium carbonate ~iller used in products of the invention is well known for other uses such as in the manufacture of PVC products which do not contain UV absorbers. Such filler is available, for instance, under the trade name Omyalite 90T. Coated calcium carbonate filler as d scribed herein is used in products of the invention in amounts broadly ranging between about 2 an~ about 50 PHR. For exterior applications such as siding, where weatherability is a problem, amounts between about 5 and about 35 PHR, more especially between about 5 and about 12 PHR are preferred.
It is preferred that the total of calcium salt of higher fatty acid present as coating on the calcium carbonate particles and any unreacted higher fatty acid be present in products of the invention in amounts not exceeding about 3 P~R. Excessive amounts o higher fatty acid or salts thereof can result in overlubrication, whereby impact, strength and homogeniety o t~se finished product is adversely affected.
As mentioned above, PVC products such as siding, intended for exterior use require the incorporation of W
absorbers in the PVC composition if excessive fading or chalking due to weathering is to be avoided. UV absorbers may be any of the materials commonly sold for such purpose, including for instance benzotriazoles, ben~ophenoner and substituted acrylonitriles. Alternatively, additional TiO2 may be incorporat~ed into the PVC composition so that the Tio2 functions as a UV a~\sorber as well as a ~hite pigment. TiO2 when used as a pigment is normally used in amounts between about 1 and about 3 PHR. When additional TiO2 is incorporated for the purpose of providing UV
protection as well as normal pigmentation, the amount of TiO2 used is normally between about 5 and about 2S PHR.
Other UV absorbers, when used, are normally used in amounts between about 0.1 and about 5 PHR.
The titanium dioxide used as a pigment or as a UV
absorber in the products of the invention may be any titanium dioxide normally used as white pigme~station in rigid PVC products. The rutile form of TiO2 is considered most satisactory since its relatively higher refractive index and reflectivity and opacity is desirable.
However, for economy it is possible to use up to about 40 wt% based on TiO2 of the anatase form. Excessive amounts of anatase are undesirable because of the recognized in~eriority of anatase relative to rutile in regard to weathering characteristics of the finished product. This is especially significant in the production of PVC building panels, such as siding, intended for exterior use.
In addition to the basic ingredients of PVC, coated calcium carbonate particles and TiO2 described above, the products of the invention may contain other ingredients normally used in rigid PVC products such as stabilizers, processing aids, lubricants, impact modifiers, additional fillers, etc. Such other ingredients, when used, frequently are used in amounts totaling between about lO
and about 40 PHR. Conventional plasticizers such as dioctyl phthalate, dihexyl phthalate, phthalate esters, etc. may also be included in the! products of the invention.
Depending on the particular physical properties desired, ot~er ingredients used, etc., plasticizer may be included in compositions of the invention in amounts up to about 30 PHR.
Rigid PVC compositions of the invention may be manufactured in any suitable conventional manner, such as to powder or pellet extrusion, calendering, thermoforming, etc., it being understood that suitable methods for manufacturing rigid PVC products such as pipes, siding, etc. are well known in the art and do not constitute a part of this invention~ While manufacturing methods are not a :, .
7~
part of the invention, it should also be understood that the particular manufacturing technique selected may effect the desirable formulation of the product of the invention within the broad limits given above.
The followiny examples illustrate preferred embodiments and advantages of the invention, but are not intended to limit the scope of the invention. In exàmples, yellowing of the various samples tested was measured after six months exposure. This particular time interval was selected because white PVC siding pigmented with TiO2 characteristically yellows to the maximum degree in about this time at the location where these tests were carried out. Following initial yellowing, chalking usually occurs followed by further yellowing. The yellowing is normally at its worst, i.e. most yellow, about 3-9 months after initial exposure depending upon the climatic conditions to which the siding is exposed.
EXAMPLE I
To evaluate the effectiveness of various forms of calcium carbonate filler in reducing yellowing of white PVC
siding, a number of siding samples were prepared from filled compounds formulated as described herein and exposed in a southerly direction at an angle of about 45 in northern New Jersey for a period of six months. The various calc um carbonate filled PVC compounds lrom which the siding panels tested were produced were formulated and extruded in a conventional manner using screw extruders and the siding panels were produced by conventional extrusion 6~3 techniquesO The method of manufacture was in all cases substantially identical. The only difference in the various panels tested was the type of calcium carbonate filler used. For these tests the formulation used comprised, in addition to the calcium carbonate filler, the following ingredients:
Ingredient Parts by Weight PVC Homopolymer (I.V. 0.90) lO0 Tin Stabilizer 1.6 Acrylic Impact Modifier 7.0 Process Aid 1.5 ~ax 0.95 Calcium stearate 2.00 TiO2 (semi-rutile) 14.00 .
Calcium carbonate particles were in each instance used in the formulation testedl in an amount of lO PHR.
Calcium carbonate particles used in forming siding samples A-F, for which test results are reported below, were as follows:
Sample A was a control sample in which no calcium carbonate filler was used.
Sample B used calcium carbonate particles wet ground to an average particle size of 2.5 microns from amorphous chalk with the maximum particle size being about lO microns (i.e. at least 90% of the particles were no larger than lO microns in size). These calcium carbonate particles were coated with calcium stearate.
79~
Sample C incorporated calcium carbonate particles obtained by wet grinding marble to an average particle si~è
of 0.7 microns with a maximum particle size of 2 microns.
These particles also were coated with calcium stearate.
Sample D incorporated amorphous calcium carbonate particles wet ground to an average particles size of 0.7 microns with a maximum particle size of about 2 microns.
These particles were coated with calcium stearate.
` Sample E incorporated calcium carbonate particles ground from a relatively crystalline calcium carbonate to an average particle size of 0.7 microns with a maximum particle diameter of about 2 microns. These particles were not coated with calcium stearate.
Sample F incorporated c:alcium carbonate particles formed by precipitation and having particle si%e diameters between 0.1 and 0.35 micron. These particles were not coated with calcium stearate.
Table I below shows the results obtained when the samples of siding described above were first exposed immediately after manufacture and after six months' exposure under the conditions described above. In Table I, values are reported for both "Hunter Color Ll' (a conventional test in which the L value measures lightness with an L value of 100 being perfectly white) and the "b"
value (another conventional test in which the b value indicates degree of yellowing with increasing yellowing causing positive changes in b value).
_g_ a~
~1 ~ . .
~ o o o ~q ~ I~ ~r o a~ cn ~1 ~ ~ ~
~ o o o o e .,, ~
~ u~ ~1 ~ ~ o ~ a~ ~
U~ ~ ~ I~ ~ _, ~ O O O
~ a) ~ ~ U~
3 u~ ~1 ~ ~ o t: a~ ~n O
U~
aJ .a I - o ~ ~ o u ~ ,.,N N ~ ~
m .~ - ~
C~ ~3 C:: ~i O
lQ _~
o e .,, ~
~ u~ ~1 ~ ~ o O ~ ,O~ ~
C~ ~ O _l O
~ ~ ~ .
U~ _~ ~D ~
cn b'~
o a a 4 U~
.IJ O ~1 0 ~ x ~ x ~l H ~ C:~
From Table I it can be seen that the control sample A containing no calcium carbonate filler has a delta b (representing the difference between the b value measured immediately after manufacture and that measured after six months' exposure) of 0.7. By contrast sample D, the only sample tested which was formulated in accordance ~ith the invention, had a delta b after six months' of only 0.1.
Other samples tested, none of which were formulated in accordance with the invention, had delta b values after six months ranging from 0.6 to 0.9. It is thus apparent that both the uncoated calcium carbonate filler and the coated calcium carbonate filler in which crystalline calcium carbonate was used were of essentially no help in improving the yellowing characteristics of the finished siding. Even the coated amorphous calcium carbonate having an average particle size of 2.5 microns (~3ample B) was unsatisfactory in this respect. Only the siding sample formulated in accordance with the invention, i.e., containing very fine ground amorphous calcium carbonate particles coated with calcium stearate, provided this unexpected advantage.
EXAMPLE II
This example illustrates the effectiveness of the finely divided amorphous calcium carbonate ~iller required by the invention in reducing yellowing of white PVC siding exposed in a southerly direction at an angle c~f about 45 degrees in Arizona for a period of nine months.
s~
The siding panels tested were produced in the same manner described above in Example I. The control sample was produced from the same formulation used in producing the - control Sample A of Example I, while the remaining samples tested in this example were produced using various amounts of the same coated calcium carbonate particles utilized in Sample D of Example I. The composition of the samples tested in this example and changes in b values of the samples tested after six and nine months are reported in Table II below.
~L~
- CCl~
a~ ~ o o o o . ~, JJ
aJ a~
~U
~a ~o .,, U~ o o o . ~ . .
H C ~11~ t~
~ ~a ~ ~ . ~ .
O ~ ~ o ~ a ~ C~ ~
C) aJ
Eit~ ~ H ~) 1~1 U~
t~
It can be seen that Examples H, I and J which contain varying amounts of coated calcium carbonate filler according to the invention exhibit substantially less ~ difference in b values than did the control Sample G which did not contain the coated calcium carbonate filler. The substantially larger differences in b value in Example II
versus those reported in Example I were due to the fact that the test panels for Example II were exposed in Arizona rather than New Jersey and were therefore subjected to considerably greater amounts of solar radiation.
EXAMPLE III
This example demonstrates the usefulness of the invention when chlorinated polyethylene (CPE) impact modifier is used. Such impact modifier is known to cause yellowing of PVC products to the extent that more expensive ac~rylic impact modifiers have in the past normally been used for PVC products intended for exterior use. As shown in ~he example, white PVC products of the invention may include ingredients such as CPE which normally promote yellowness upon prolonged exposure of the product to the sun. For this evaluation four compounds identified below as compounds K,L, M & N were tested according to the procedure outlined in Example I, Compounds K and M had the following compositions.
Compound K Compound Ingredient (PHR) (PHR) PVC Homopolymer (0.9 I.V.) 100 100 Tin Stabilizer 1.6 1.6 CPE 10.0 15.0 Process Aids 1.5 1.5 Calcium Stearate 2.0 2.0 Wax 0.95 0 95 i2 7.0 7 0 10Compound L was identical witb compound K except for the addition of 20 PHR of the coated calcium carbonate of Sample D of Example I and compound N was identical with compound M except for the addit:ion of 35 PHR of the coated calcium carbonate of Sample D of Example I. When formed 15into test panels and evaluat~ed for changes in b value according to procedures outlines in Example I, the following results were obtained.
Sample: R L M N
Difference in value after 6 2.2 1.11 2.58 1.24 mos. exposure
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. White PVC composition comprising:
a) polyvinyl chloride;
b) between about 5 and about 35 lbs. per 100 lbs. resin of finely divided amorphous calcium carbonate filler having an average particle size between about 0.1 and about 1.0 micron with at least 90% of such calcium carbonate particles used hav-ing a maximum size of not more than 2 microns, individual parti-cles of such filler being coated with calcium salt of a higher fatty acid; and c) TiO2 present as pigment and as ultraviolet light absorber in a total amount between about 5 and about 25 lbs.
per 100 lbs. resin.
a) polyvinyl chloride;
b) between about 5 and about 35 lbs. per 100 lbs. resin of finely divided amorphous calcium carbonate filler having an average particle size between about 0.1 and about 1.0 micron with at least 90% of such calcium carbonate particles used hav-ing a maximum size of not more than 2 microns, individual parti-cles of such filler being coated with calcium salt of a higher fatty acid; and c) TiO2 present as pigment and as ultraviolet light absorber in a total amount between about 5 and about 25 lbs.
per 100 lbs. resin.
2. Composition according to claim 1 wherein the calcium salt of a higher fatty acid is calcium stearate.
3. Composition according to claim 2 wherein the TiO2 is rutile containing between 0 and about 40% anatase.
4. Composition according to claim 3 wherein the polyvinyl chloride comprises at least about 80 percent vinyl chloride polymer.
5. A rigid plastic building panel comprising the composi-tion of claim 1.
6. A rigid plastic building panel comprising the composition of claim 4.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US79235077A | 1977-04-29 | 1977-04-29 | |
| US792,350 | 1977-04-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1116769A true CA1116769A (en) | 1982-01-19 |
Family
ID=25156598
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000298728A Expired CA1116769A (en) | 1977-04-29 | 1978-03-13 | Caco.sub.3 filled siding with improved weathering |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS53134850A (en) |
| AU (1) | AU515451B2 (en) |
| CA (1) | CA1116769A (en) |
| DE (1) | DE2815176A1 (en) |
| FR (1) | FR2388854A1 (en) |
| GB (1) | GB1564087A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2480771A1 (en) * | 1980-04-21 | 1981-10-23 | Rhone Poulenc Ind | NOVEL CALCIUM CARBONATE COMPOSITION, METHOD FOR MANUFACTURING SAME, AND APPLICATION THEREOF IN POLYMER COMPOSITIONS |
| JPH08208923A (en) * | 1995-02-03 | 1996-08-13 | Mitsubishi Plastics Ind Ltd | Polyvinyl chloride resin composition |
| WO1996026333A1 (en) * | 1995-02-24 | 1996-08-29 | Anderson Carl E | Improved pvc building trim |
| US20030176544A1 (en) | 2002-03-15 | 2003-09-18 | Polyone Corporation | Rigid PVC compounding compositions exhibiting weather resistance and PVC degradation resistance in hot sunny climates |
| RU2489459C1 (en) * | 2011-12-26 | 2013-08-10 | Федеральное государственное унитарное предприятие "Научно-исследовательский институт химии и технологии полимеров имени академика В.А. Каргина с опытным заводом" (ФГУП "НИИ полимеров") | Polyvinyl chloride-based composition for insulation and sheaths of wires and cables |
| FR3001222B1 (en) * | 2013-01-24 | 2016-01-22 | Arkema France | HALOGEN POLYMER COMPOSITE COMPOSITION, PROCESS FOR PREPARING THE SAME, AND USE THEREOF |
| CN111372991B (en) | 2017-09-15 | 2023-11-17 | 吉昂功能材料(东莞)有限公司 | Flame retardant poly (vinyl chloride) composites |
-
1978
- 1978-03-13 CA CA000298728A patent/CA1116769A/en not_active Expired
- 1978-03-20 AU AU34303/78A patent/AU515451B2/en not_active Expired
- 1978-04-07 DE DE19782815176 patent/DE2815176A1/en not_active Withdrawn
- 1978-04-12 GB GB1442978A patent/GB1564087A/en not_active Expired
- 1978-04-24 JP JP4796378A patent/JPS53134850A/en active Pending
- 1978-04-28 FR FR7812671A patent/FR2388854A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB1564087A (en) | 1980-04-02 |
| FR2388854A1 (en) | 1978-11-24 |
| AU3430378A (en) | 1979-09-27 |
| DE2815176A1 (en) | 1978-11-02 |
| AU515451B2 (en) | 1981-04-02 |
| JPS53134850A (en) | 1978-11-24 |
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