WO2003008707A1 - Papier fabrique au moyen de pulpe d'acacia et son procede de fabrication - Google Patents

Papier fabrique au moyen de pulpe d'acacia et son procede de fabrication Download PDF

Info

Publication number
WO2003008707A1
WO2003008707A1 PCT/JP2002/007349 JP0207349W WO03008707A1 WO 2003008707 A1 WO2003008707 A1 WO 2003008707A1 JP 0207349 W JP0207349 W JP 0207349W WO 03008707 A1 WO03008707 A1 WO 03008707A1
Authority
WO
WIPO (PCT)
Prior art keywords
pulp
acacia
paper
mixed
beating
Prior art date
Application number
PCT/JP2002/007349
Other languages
English (en)
Japanese (ja)
Inventor
Chandra Heriyanto
Jonny Hidajat
Ming Tsung Tsai
Original Assignee
Pt. Pabrik Kertas Tjiwi Kimia Tbk.
Suzuki, Rikio
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Pt. Pabrik Kertas Tjiwi Kimia Tbk., Suzuki, Rikio filed Critical Pt. Pabrik Kertas Tjiwi Kimia Tbk.
Publication of WO2003008707A1 publication Critical patent/WO2003008707A1/fr

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only

Definitions

  • the present invention relates to a paper made mainly from mixed southern pulp, and more particularly to paper using acacia pulp in place of softwood bleached crab pulp blended in mixed southern pulp and a method for producing the same.
  • paper strength is affected by various factors.
  • paper is composed of fibers, and the strength of these fibers is a major factor.
  • the fiber strength mainly depends on the cell thickness of the fiber, and when the fiber becomes loin, the web also becomes loin.
  • the second factor is the hydrogen bonding between the fiber surfaces.
  • the surface of the fiber is covered with hydroxyl groups, which greatly affect hydrogen bonding. And this hydrogen bond becomes a strong bond if it has a high density effect, although its bonding force is weak. This can be enhanced by considering the following perspectives.
  • the total hydrogen bonding between the two fiber surfaces is affected by the size of the contact area.
  • the contact area depends on the properties of the fiber, the preparation process, the fiber length, the fibrillation, the flexibility and the diameter ratio.
  • the fiber length is likely to cause Can form a stronger web.
  • beating in the preparation process has the effect of promoting the formation of fibers into fibers and increasing the contact surface area. In this way, the overall hydrogen bond strength can be increased.
  • the long fibers of bleached softwood kraft pulp become entangled with the pulp fibers of the mixed South Sea wood, and the hydrogen bonds cause strong fiber bonding, which increases the strength of the paper.
  • Increasing paper strength is an important factor not only for improving paper quality, but also for operating efficiency of paper machines.
  • softwood bleached kraft pulp is very expensive compared to mixed southern pulp, so if the amount of softwood bleached kraft pulp is increased to increase the paper strength, the softwood bleached kraft pulp may be mixed. There was a problem that it became expensive in proportion to the amount. Since the strength of the paper is affected by the factors mentioned above, other pulp with similar properties should be applicable to improve the strength of the paper.
  • Acacia pulp unlike softwood bleached kraft pulp, cannot increase web strength due to fiber length.
  • the fiber length of acacia pulp is shorter than softwood bleached kraft pulp as well as mixed southern pulp, but it is easily friable and is divided into thin fibrous forms as shown in the examples described later.
  • the present invention provides a paper made from mixed southern seawood as a main raw material, which has properties comparable to paper made from softwood bleached kraft pulp and paper made from mixed southern seawood pulp, but which is even less expensive. And to provide a method for producing the paper.
  • the present invention relates to a paper made from a mixed pulp of mixed southern and acacia wood, which has properties comparable to paper made from 10% softwood bleached kraft pulp and 90% mixed southern pulp. It is an object of the present invention to provide a paper which is more inexpensive while having the same, and to provide a method for producing the paper.
  • the mixed southern pulp in the present invention is mainly composed of pulp of merantis (Meranti Group, commonly known as meranti) because of its easy availability, and also includes Rinba Campuran Group (Rimba Campuran Group, We used pulp with local names such as Punak, Kempas, Balan, Bintangur, and Pisang pisang, but especially limited to this. Rather than the southern lumber commonly used in the manufacture of paper when needed It is clear that the pulp can be used by mixing as appropriate. Disclosure of the invention
  • a paper characterized in that mixed South Sea pulp is used as a main raw material and a prescribed amount of acacia pulp is blended with the pulp.
  • the paper of the present invention is characterized in that the mixed South Sea pulp is mainly composed of pulp of Meranti (Meranti Group, commonly known as Meranti) and, in addition, Rimba Camp uran Group (currently: Tunana Puna) ), Gen'no ⁇ 0 scan (empas), Roh run (Balan), human ,, Ntanku Les (Bintangur), is obtained by mixing a combination of some of Nono 0 Norre-flops of Pisanpisan (Pisang pisang), etc.), acacia
  • the blending amount of the wood pulp is 20 to 30% by weight, preferably 25 to 30% by weight.
  • both pulp are beaten in different beating lines, respectively.
  • a manufacturing method is provided.
  • the method for producing paper of the present invention is characterized in that the mixed southern pulp is mainly made of pulp of merantis (Meranti Group, commonly known as merantik), and is also used as a pulp of Rimba Campuran Group (local name: Punak). ), Kempas, Nolan (Balan), Bintangurore (Bintangur), Pisampisan (Pisang pisang), etc.).
  • Acacia wood The pulp has a blending amount of 20 to 30% by weight and a beating degree in a range of 400 CSF to 500 CSF (Canadian Standard Freeness), preferably 25 to 30 CSF. a weight 0/0, characterized by beating the beating degree in the range of 4 0 0 CSF ⁇ 5 0 0 CSF .
  • Table 1 summarizes the results of examining the fiber length and roughness (degree of fiber diameter) before and at a predetermined degree of beating of each pulp.
  • LL length weighted average fiber length
  • LW weight weighted average fiber length (according to JAPAN TAPP I paper pulp test method No. 52-89).
  • those of the LPP, Inc. meranti class:. about 70 weight / 0, lymph camp orchids: about 30 weight 0/0 was used, as the bleached softwood kraft pulp had use of a commercially available Leaf River (trade name).
  • IKPP Acacia Acacia pulp manufactured by Indah Kiat Pulp & Paper
  • LPP MTH Mixed southern pulp manufactured by Lontar Papyrus Pulp & Paper
  • LR NBKP Leaf River: Trade name of bleached softwood kraft pulp (USA)
  • acacia pulp is a very thin fiber compared to mixed southern pulp and softwood bleached kraft pulp, and therefore has a low roughness, especially when beaten to 400 CSF.
  • the beating process has a greater effect on the reduction in roughness than on the reduction in fiber length.
  • the fiber length is reduced to only 95% (weight-weighted average fiber length), but the roughness is reduced to 60%.
  • Fig. 1 shows a schematic drawing of the contact state of each fiber.
  • A shows the case of mixed southern timber (MTH) and acacia (Ac acia) timber pulp
  • (b) shows the case of softwood bleached kraft pulp (NBKP) and mixed southern timber (MTH).
  • Fig. 2 is a scanning electron micrograph of the acacia pulp with various degrees of beating, where (a) is before beating, (b) is 55 OCSF, (c) is 500C SF, and (d) ) Indicates a beating degree of 45 OCSF, and (e) indicates a beating degree of 400 CSF.
  • Fig. 1 is a scanning electron micrograph of the acacia pulp with various degrees of beating, where (a) is before beating, (b) is 55 OCSF, (c) is 500C SF, and (d) ) Indicates a beating degree of 45 OCSF, and (e) indicates a beating degree of 400 CSF.
  • FIG. 3 shows scanning electron micrographs of the softwood bleached kraft pulp when the degree of beating was changed.
  • A shows the result before beating, and
  • b shows the result when the degree of beating was 500 CSF.
  • Fig. 4 shows scanning electron micrographs of the mixed South Sea pulp with different degrees of beating, (a) before the beating and (b) with the degree of beating 50 OCSF.
  • Paper sheets ranged from 74 to 76 gZm2 and were made on an automatic handmade machine.
  • the raw material is a mixture of acacia wood pulp mixed in a range of 20-35% (weight%, the same applies hereinafter) to 500 cc of mixed South Sea wood pulp (ex. Manufactured by IKPP).
  • the beating degree was independently beaten in the range of 400 CSF to 550 CSF. The reason is that acacia pulp is easier to beat than mixed southern seawood, so it is necessary to beat acacia pulp on a single line.
  • a sheet made from 10% softwood bleached kraft pulp 500CSF (90% mixed South Sea wood pulp) (hereinafter referred to as “10% NBKP”) and a sheet made from 100% mixed South Sea wood pulp (hereinafter “100% MTH ”).
  • Figures 6 to 13 show the relationship between the raw material blending and the degree of beating with the individual properties of paper.
  • the relationship with the composite characteristic value is shown in FIGS. 14 and 15. Since the measured value of stiffness (stiffness) includes the basis weight, all characteristic values other than stiffness are represented by index values, that is, each characteristic value divided by the basis weight.
  • Fig. 6 shows the relationship of stiffness when the mixing ratio of acacia pulp was changed
  • Fig. 7 shows the relationship of stiffness when the degree of beating of acacia pulp was changed.
  • acacia pulp there is no certain tendency in the mixing ratio of acacia pulp except 400 CSF, but it is the highest at 400 CSF, and the content of acacia pulp is 20%. It can be seen that stiffness equal to or greater than 10% NB KP was obtained at% or more. The reason for this is that the fibers of the acacia pulp sufficiently fill the voids between the fibers of the mixed southern seawood, i.e. Conceivable.
  • the stiffness increases as the beating degree of the acacia pulp increases from 450CSF to 400CSF, and the acacia pulp content is 25% or more. It can be seen that the acacia pulp has a beating degree of about 420 CSF or less, and stiffness equivalent to or higher than that of 10% NBKP is obtained.
  • the stiffness of the acacia pulp content is about 22% or more and the acacia pulp content is about 22% or more, which is equivalent to or higher than that of 10% NBKP, at least if the refining degree of the acacia pulp is more than about 420CSF. Can be expected to be obtained.
  • Fig. 8 shows the change in the tensile strength index when the mixing ratio of the acacia pulp was changed
  • Fig. 9 shows the tensile strength index when the beating degree of the acacia pulp was changed.
  • the optimal value of the tensile strength index is obtained when the mixing ratio of acacia pulp is 24% to 30% and the beating degree is in the range of 400CSF to 500CSF.
  • Most sheets have a tensile strength index approximately equal to or greater than 10% NBKP, except in the case of Acacia pulp content of 20% to 30%, except for 550 CSF.
  • NBKP tensile strength index
  • the fibers of acacia pulp do not contribute to the improvement of the tensile strength because the fibers of the acacia pulp are not soild and are not divided into thin fibrous forms.
  • higher values were obtained than those with 100% MTH. LPPAE in each figure indicates 100% MTH.
  • the acacia pulp content is 25% to 30%
  • the beating degree is in the range of 400CSF to 520CSF
  • the tensile strength index is almost equal to or higher than 10% NBKP. I have.
  • Burst strength tends to differ from stiffness (stiffness) and tensile strength index.
  • Fig. 10 and Fig. 11 As the mixing ratio of acacia pulp increases, the value of the burst strength index increases. In the numerical range measured in this example, no peak appeared for the content of acacia pulp, while the effect of beating degree showed an optimum burst strength index at 450 CSF. Except at the time of 550 CSF, the burst strength index was equal to or higher than that of 10% NBKP when the content of acacia pulp was 20% or more.
  • Figure 12 shows the change in the tear strength index when the mixing ratio of the acacia pulp is changed
  • Fig. 13 shows the change in the tear strength index when the beating degree of the acacia pulp is changed.
  • acacia pulp with a beating degree of 400 CSF the content of acacia pulp is in the range of 20% to 30%, which is also comparable to that of 10% NBKP.
  • the 400 CSF sample (well beaten fiber) fills the voids in the fiber of the mixed southern pulp and results in a high density paper with a tear strength value. Is up.
  • a certain tear strength is obtained due to the strength of the fiber itself.
  • Samples with other formulations tend to be more complicated due to the complex web structure of mixed southern pulp and acacia pulp.
  • the composite property values (burst strength, tensile strength and tear strength) are shown in FIGS. In this figure, stiffness (rigidity) is omitted because it is less important than the other three properties.
  • Figure 14 shows the composite value of each property, with some samples having positive values.
  • Figure 15 shows the values for each property value separately.All samples with acacia pulp of 25% -400CSF, 20% -500CSF and 30% -500CSF have positive values. have.
  • 10% NBKP can be obtained by using mixed Nanyo-Acacia mixed pulp with the mixed amount of acacia pulp of 25% to 30% and the degree of beating around 45 OCS F. Paper with excellent properties can be obtained, but the content of acacia pulp is selected from 20 to 35% and the beating degree of acacia pulp is selected from 400 CSF to 500 CSF depending on the value of the properties to be considered. This makes it possible to produce paper with properties that are about the same or better than 10% NB KP. Wear.
  • acacia pulp is less expensive than softwood bleached kraft pulp, so chemical costs (fillers, wet end starch, retention agents, sizing agents, etc.) and beating costs (acacia pulp is easier to beat) Is the same, the paper production cost when using a mixed pulp of mixed southern seawood and acacia is compared with the case of using a mixed pulp of 10% softwood bleached kraft pulp and 90% southern seawood. And acacia pulp can be made cheaper by the price difference.
  • the paper obtained from the mixed southern seawood-acacia pulp according to the present invention has almost the same or higher characteristic values as the paper using 90% mixed southern seawood-1% softwood bleached kraft pulp. It was confirmed that mixed South Seawood-Acacia wood pulp could be sufficiently replaced by mixed South Sea wood single-leaf bleached kraft pulp.
  • Acacia pulp is also cheaper than softwood bleached kraft pulp, so it has the same characteristics, but its production cost can be reduced by the price difference between the two pulp.
  • Figure 1 is a schematic drawing of the contact state of each fiber.
  • A shows the case of mixed southern seawood (MTH) and acacia (Ac acia) pulp, and (b) shows softwood bleached kraft pulp (NBKP). ) And mixed southern seawood (MTH).
  • Figure 2 shows scanning electron micrographs of the acacia pulp with various degrees of beating, where (a) is before beating, (b) is 550CSF, and (c) is 500C. SF, (d) shows the degree of beating degree of 450 CSF, (e) shows the case of beating degree of 400 CSF.
  • Fig. 3 is a scanning electron micrograph when the degree of beating of softwood bleached kraft pulp is changed. (A) shows the case before beating and (b) shows the case with a beating degree of 500 CSF.
  • FIGS. 4A and 4B are scanning electron micrographs when the degree of beating of the mixed southern pulp was changed.
  • FIG. 4A shows the state before the beating and
  • FIG. 4B shows the state when the degree of beating was 500 CSF.
  • Fig. 5 is a schematic diagram showing the difference in beating effect due to the difference in raw materials, where (a) is the fiber of bleached softwood bleached kraft pulp, (b) is the fiber of beaten mixed southern seawood pulp, and (c) Indicates the case of beaten acacia pulp fibers.
  • Figure 6 shows the relationship of stiffness (rigidity) when the mixing ratio of acacia pulp was changed.
  • FIG. 7 is a diagram showing the relationship of stiffness when the degree of beating of acacia pulp is changed.
  • Figure 8 shows the tensile strength when the mixing ratio of acacia pulp was changed.
  • FIG. 1 A first figure.
  • FIG. 9 is a diagram showing a change in tensile strength when the degree of beating of acacia pulp is changed.
  • Figure 10 shows the rupture resistance when the mixing ratio of acacia pulp was changed.
  • FIG. 1 A first figure.
  • FIG. 11 is a diagram showing a change in burst resistance indettas when the degree of beating of acacia pulp is changed.
  • FIG. 12 is a diagram showing a change in the tear resistance index when the mixing ratio of acacia pulp is changed.
  • FIG. 13 is a diagram showing the change in the tear resistance index when the degree of beating of acacia pulp is changed.
  • FIG. 14 is a graph showing the total characteristic value difference ratio of akashia pulp-containing paper to 10% NBKP paper.
  • FIG. 15 is a diagram showing a synthetic property value difference ratio of acacia pulp-containing paper to 10% NBKP paper.

Landscapes

  • Paper (AREA)

Abstract

L'invention concerne du papier contenant de la pâte de bois d'Asie du sud-est en tant que constituant principal, dont les propriétés sont comparables à du papier fabriqué avec 10 % de pulpe lessivée de bois doux et 90 % de pulpe de bois d'Asie du sud-est mélangée, ce qui présente une économie réelle. Papier caractérisé par une pulpe de bois d'Asie du sud-est mélangée en tant que constituant principal auquel on a ajouté une quantité définie de pulpe d'acacia. On bat ces pulpes dans différentes chaînes de battage afin de fabriquer le papier. Le contenu en pulpe d'acacia est situé entre 20 et 30 % en poids, de préférence, entre 25 et 30 % en poids et le degré de battage est situé entre 400 et 500 CSF.
PCT/JP2002/007349 2001-07-19 2002-07-19 Papier fabrique au moyen de pulpe d'acacia et son procede de fabrication WO2003008707A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001-220440 2001-07-19
JP2001220440A JP3966701B2 (ja) 2001-07-19 2001-07-19 アカシア材パルプを使用した紙およびその製造方法

Publications (1)

Publication Number Publication Date
WO2003008707A1 true WO2003008707A1 (fr) 2003-01-30

Family

ID=19054259

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2002/007349 WO2003008707A1 (fr) 2001-07-19 2002-07-19 Papier fabrique au moyen de pulpe d'acacia et son procede de fabrication

Country Status (2)

Country Link
JP (1) JP3966701B2 (fr)
WO (1) WO2003008707A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1876168A1 (fr) 2006-07-04 2008-01-09 Evonik Degussa GmbH Procédé destiné à la fabrication d'amides d'acides béta-amino-alpha-hydroxy-carbone
WO2022006608A1 (fr) 2020-07-10 2022-01-13 Mondi Ag Procédé pour produire des pailles à base de fibres cellulosiques

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4793244B2 (ja) * 2006-12-13 2011-10-12 パナソニック株式会社 スピーカ用ダストキャップ
JP4793015B2 (ja) * 2006-02-20 2011-10-12 パナソニック株式会社 スピーカ用振動板およびこれを用いたスピーカならびにこのスピーカを用いた電子機器および装置
JP4793017B2 (ja) * 2006-02-20 2011-10-12 パナソニック株式会社 スピーカ用サブコーンおよびこれを用いたスピーカならびにこのスピーカを用いた電子機器および装置
JP4793016B2 (ja) * 2006-02-20 2011-10-12 パナソニック株式会社 スピーカ用ダストキャップおよびこれを用いたスピーカならびにこのスピーカを用いた電子機器および装置
US8199964B2 (en) 2006-02-20 2012-06-12 Panasonic Corporation Speaker diaphragm, speaker dust cap, speaker sub-cone, speaker using these components, and electronic apparatus using the same
JP4793222B2 (ja) * 2006-11-02 2011-10-12 パナソニック株式会社 スピーカ用振動板
JP5332501B2 (ja) * 2008-10-27 2013-11-06 王子ホールディングス株式会社 印刷用塗工紙
SG10201503693PA (en) * 2015-05-11 2016-12-29 Rge Pte Ltd A Pulp Fiber Composition
JP2019163578A (ja) * 2018-03-16 2019-09-26 王子ホールディングス株式会社 発泡断熱紙容器用紙基材、発泡断熱紙容器用シートおよび発泡断熱紙容器
JP7215189B2 (ja) * 2018-03-16 2023-01-31 王子ホールディングス株式会社 発泡断熱紙容器用紙基材、発泡断熱紙容器用シートおよび発泡断熱紙容器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58197400A (ja) * 1982-05-11 1983-11-17 ダイセル化学工業株式会社 紙力増強方法
JPH08109591A (ja) * 1994-10-05 1996-04-30 Honshu Paper Co Ltd 強度を向上した紙および板紙及びその製造方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58197400A (ja) * 1982-05-11 1983-11-17 ダイセル化学工業株式会社 紙力増強方法
JPH08109591A (ja) * 1994-10-05 1996-04-30 Honshu Paper Co Ltd 強度を向上した紙および板紙及びその製造方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1876168A1 (fr) 2006-07-04 2008-01-09 Evonik Degussa GmbH Procédé destiné à la fabrication d'amides d'acides béta-amino-alpha-hydroxy-carbone
WO2022006608A1 (fr) 2020-07-10 2022-01-13 Mondi Ag Procédé pour produire des pailles à base de fibres cellulosiques

Also Published As

Publication number Publication date
JP3966701B2 (ja) 2007-08-29
JP2003027388A (ja) 2003-01-29

Similar Documents

Publication Publication Date Title
US11634863B2 (en) Method to produce composite-enhanced market pulp and paper
CN204325807U (zh) 多层纸板
WO2003008707A1 (fr) Papier fabrique au moyen de pulpe d'acacia et son procede de fabrication
CN102124162A (zh) 工程化复合产品及其制造方法
CN112575618A (zh) 多层纸板
Brodin et al. Preparation of individualised lignocellulose microfibrils based on thermomechanical pulp and their effect on paper properties
Kasmani et al. Effect of nano-cellulose on the improvement of the properties of paper newspaper produced from chemi-mechanical pulping
WO2021001751A1 (fr) Composition de fibre de cellulose raffinée
WO2016140609A1 (fr) Mélange de pâte destiné à la production de produit de carton présentant une grande résistance dans la direction z
Laukala et al. Influence of pulp type on the three-dimensional thermomechanical convertibility of paperboard
JPH08188980A (ja) 透明紙
Fatehi et al. Interaction of cationic modified poly vinyl alcohol with high yield pulp
Liu et al. Using cationic polyvinyl alcohol (C-PVA) to improve the strength of wood-free papers containing high-yield pulp (HYP)
EP3833813A1 (fr) Mélange de fibres, procédé de production d'un mélange de fibres et produit en carton comprenant un mélange de fibres
US20200340182A1 (en) A cellulose paper composite and process for preparation thereof
Khantayanuwong et al. Physical Properties of Handsheets Derived from Coi (Streblus asper Lour.) Pulp Fiber as Papermaking Material Traced from Ancient Times.
JPH08109591A (ja) 強度を向上した紙および板紙及びその製造方法
Jahan et al. Reinforcing potential of jute pulp with Trema orientalis (nalita) pulp.
KR100750875B1 (ko) 개질된 목질섬유분을 이용한 벌크 및 휨강도가 증가된종이판지의 제조방법
Zhang et al. Energy saving potential of high yield pulp (HYP) application by addition of small amounts of bleached wheat straw pulp
EP0004833B1 (fr) Produit fibreux semblable au papier et procédé de fabrication d'un tel produit
JP7234866B2 (ja) クラフト紙及びその製造方法
Potulski et al. Nanofibrillated cellulose applied as reinforcement for short-fiber paper.
Pego et al. Blended paper: physical, optical, structural, and interfiber bonding analysis
EP4310249A1 (fr) Produits de papier translucides

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CN ID KR US

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)