CN112760979A - 一种抗污聚丙烯无纺布及其制备方法 - Google Patents

一种抗污聚丙烯无纺布及其制备方法 Download PDF

Info

Publication number
CN112760979A
CN112760979A CN202011606745.4A CN202011606745A CN112760979A CN 112760979 A CN112760979 A CN 112760979A CN 202011606745 A CN202011606745 A CN 202011606745A CN 112760979 A CN112760979 A CN 112760979A
Authority
CN
China
Prior art keywords
fouling
woven fabric
polypropylene
polypropylene non
preparing
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.)
Pending
Application number
CN202011606745.4A
Other languages
English (en)
Inventor
史斌
姚启明
史清友
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui Linquan Wanlong Plastic Packaging Co ltd
Original Assignee
Anhui Linquan Wanlong Plastic Packaging Co ltd
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 Anhui Linquan Wanlong Plastic Packaging Co ltd filed Critical Anhui Linquan Wanlong Plastic Packaging Co ltd
Priority to CN202011606745.4A priority Critical patent/CN112760979A/zh
Publication of CN112760979A publication Critical patent/CN112760979A/zh
Pending legal-status Critical Current

Links

Classifications

    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06MTREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M14/00Graft polymerisation of monomers containing carbon-to-carbon unsaturated bonds on to fibres, threads, yarns, fabrics, or fibrous goods made from such materials
    • D06M14/18Graft polymerisation of monomers containing carbon-to-carbon unsaturated bonds on to fibres, threads, yarns, fabrics, or fibrous goods made from such materials using wave energy or particle radiation
    • D06M14/26Graft polymerisation of monomers containing carbon-to-carbon unsaturated bonds on to fibres, threads, yarns, fabrics, or fibrous goods made from such materials using wave energy or particle radiation on to materials of synthetic origin
    • D06M14/28Graft polymerisation of monomers containing carbon-to-carbon unsaturated bonds on to fibres, threads, yarns, fabrics, or fibrous goods made from such materials using wave energy or particle radiation on to materials of synthetic origin of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00General methods for the manufacture of artificial filaments or the like
    • D01F1/02Addition of substances to the spinning solution or to the melt
    • D01F1/10Other agents for modifying properties
    • D01F1/103Agents inhibiting growth of microorganisms
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00General methods for the manufacture of artificial filaments or the like
    • D01F1/02Addition of substances to the spinning solution or to the melt
    • D01F1/10Other agents for modifying properties
    • D01F1/106Radiation shielding agents, e.g. absorbing, reflecting agents
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/44Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
    • D01F6/46Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polyolefins
    • DTEXTILES; PAPER
    • D04BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04HMAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4282Addition polymers
    • D04H1/4291Olefin series
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06MTREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M16/00Biochemical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. enzymatic
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06MTREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2101/00Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
    • D06M2101/16Synthetic fibres, other than mineral fibres
    • D06M2101/18Synthetic fibres consisting of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M2101/20Polyalkenes, polymers or copolymers of compounds with alkenyl groups bonded to aromatic groups
    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06MTREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2200/00Functionality of the treatment composition and/or properties imparted to the textile material
    • D06M2200/01Stain or soil resistance

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Microbiology (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Abstract

本发明公开了一种抗污聚丙烯无纺布,包括基布和粘附在基布表面的抗污层,基布的原料按重量份包括:聚丙烯80‑90份、硅烷偶联剂改性二氧化钛10‑20份、引发剂0.05‑0.1份、相容剂1‑2份;抗污层为聚甲基丙烯酸十二氟庚酯层。本发明还公开了上述抗污聚丙烯无纺布的制备方法,包括如下步骤:S1、在基布表面涂覆二苯甲酮溶液,浸润,然后紫外光照射,洗涤,干燥得到布料A;S2、在布料A表面涂覆甲基丙烯酸十二氟庚酯溶液,浸润,然后紫外光照射,洗涤,干燥得到布抗污聚丙烯无纺布。本发明表面能较低,具有良好的抗污性能。

Description

一种抗污聚丙烯无纺布及其制备方法
技术领域
本发明涉及无纺布技术领域,尤其涉及一种抗污聚丙烯无纺布及其制备方法。
背景技术
聚丙烯无纺布具有蓬松、手感好、柔软度适中、透气性好等优点,可以制成手提袋、包装袋等产品,美观大方,可以多次使用,且聚丙烯可以有效地降解,对环境污染少。但是在聚丙烯无纺布制备过程中,常经过水刺、针刺等步骤,会在无纺布表面留下凹印,容易聚集污染物和细菌,需要提高其抗菌抗污性能。
发明内容
基于背景技术存在的技术问题,本发明提出了一种抗污聚丙烯无纺布及其制备方法,本发明表面能较低,具有良好的机械性能和抗污性能。
本发明提出了一种抗污聚丙烯无纺布,包括基布和粘附在基布表面的抗污层,基布的原料按重量份包括:聚丙烯80-90份、硅烷偶联剂改性二氧化钛10-20份、引发剂0.05-0.1份、相容剂1-2份;抗污层为聚甲基丙烯酸十二氟庚酯层。
优选地,硅烷偶联剂为含不饱和双键的硅烷偶联剂。
上述引发剂可以为过氧化二异丙苯等。
上述含不饱和双键的硅烷偶联剂可以为乙烯基三甲氧基硅烷、乙烯基三乙氧基硅烷、γ-甲基丙烯酰氧基丙基三甲氧基硅烷等。
上述相容剂可以为马来酸酐接枝相容剂等。
本发明还提出了上述抗污聚丙烯无纺布的制备方法,包括如下步骤:
S1、在基布表面涂覆二苯甲酮溶液,浸润,然后紫外光照射,洗涤,干燥得到布料A;
S2、在布料A表面涂覆甲基丙烯酸十二氟庚酯溶液,浸润,然后紫外光照射,洗涤,干燥得到布抗污聚丙烯无纺布。
优选地,在S1中,紫外光照射10-20s。
优选地,在S2中,紫外光照射3-5min。
优选地,浸润时间均≤30s。
优选地,在S1中,二苯甲酮溶液的浓度为20-30mmol/L。
优选地,在S1中,二苯甲酮溶液的溶剂为正庚烷。
优选地,在S2中,甲基丙烯酸十二氟庚酯溶液的含量为8-10wt%。
优选地,在S2中,甲基丙烯酸十二氟庚酯溶液的溶剂为正庚烷。
不规定二苯甲酮溶液、甲基丙烯酸十二氟庚酯溶液的涂覆量,能均匀涂覆并浸润聚丙烯无纺布即可。
有益效果:
本发明先让光引发剂二苯甲酮接枝在聚丙烯无纺布表面,然后再接枝甲基丙烯酸十二氟庚酯,在无纺布表面引入了大量氟元素,使得无纺布表面能大幅降低,抵抗污染物和细菌的粘附,达到很好的抗污抗菌性能;另外接枝二苯甲酮后,进行洗涤可以洗去未接枝的二苯甲酮,避免未接枝的二苯甲酮与甲基丙烯酸十二氟庚酯共聚,影响甲基丙烯酸十二氟庚酯与聚丙烯无纺布接枝的问题;
另外含不饱和双键的硅烷偶联剂改性二氧化钛,与聚丙烯熔融共混制备无纺布的时候,在引发剂作用下,可以接枝到聚丙烯中,可以提高本发明的抗紫外线性能和抗菌性能。
具体实施方式
下面,通过具体实施例对本发明的技术方案进行详细说明。
实施例1
一种抗污聚丙烯无纺布,包括基布和粘附在基布表面的抗污层,基布的原料按重量份包括:聚丙烯80g、乙烯基三甲氧基硅烷改性二氧化钛20g、过氧化二异丙苯0.05g、聚丙烯接枝马来酸酐共聚物2g;抗污层为聚甲基丙烯酸十二氟庚酯层。
上述抗污聚丙烯无纺布的制备方法,包括如下步骤:
S1、取尺寸为15*15cm,克重为70g/m2的聚丙烯无纺布,依次用乙醇、水超声清洗20min,烘干得到基布;
在基布表面涂覆10ml浓度为20mmol/L二苯甲酮的正庚烷溶液,浸润20s,然后用紫外光照射20s,用正庚烷洗涤2次,晾干得到布料A;
S2、在布料A表面涂覆20ml含量为8wt%甲基丙烯酸十二氟庚酯的正庚烷溶液,浸润20s,然后用紫外光照射5min,依次用正庚烷、乙醇洗涤2次,然后用水冲洗,于50℃烘干得到布抗污聚丙烯无纺布。
实施例2
一种抗污聚丙烯无纺布,包括基布和粘附在基布表面的抗污层,基布的原料按重量份包括:聚丙烯90g、乙烯基三甲氧基硅烷改性二氧化钛10g、过氧化二异丙苯0.1g、聚丙烯接枝马来酸酐共聚物1g;抗污层为聚甲基丙烯酸十二氟庚酯层。
上述抗污聚丙烯无纺布的制备方法,包括如下步骤:
S1、取尺寸为15*15cm,克重为70g/m2的聚丙烯无纺布,依次用乙醇、水超声清洗20min,烘干得到基布;
在基布表面涂覆10ml浓度为30mmol/L二苯甲酮的正庚烷溶液,浸润20s,然后用紫外光照射10s,用正庚烷洗涤2次,晾干得到布料A;
S2、在布料A表面涂覆20ml含量为10wt%甲基丙烯酸十二氟庚酯的正庚烷溶液,浸润20s,然后用紫外光照射3min,依次用正庚烷、乙醇洗涤2次,然后用水冲洗,于50℃烘干得到布抗污聚丙烯无纺布。
实施例3
一种抗污聚丙烯无纺布,包括基布和粘附在基布表面的抗污层,基布的原料按重量份包括:聚丙烯85g、乙烯基三甲氧基硅烷改性二氧化钛15g、过氧化二异丙苯0.07g、聚丙烯接枝马来酸酐共聚物1.5g;抗污层为聚甲基丙烯酸十二氟庚酯层。
上述抗污聚丙烯无纺布的制备方法,包括如下步骤:
S1、取尺寸为15*15cm,克重为70g/m2的聚丙烯无纺布,依次用乙醇、水超声清洗20min,烘干得到基布;
在基布表面涂覆10ml浓度为25mmol/L二苯甲酮的正庚烷溶液,浸润20s,然后用紫外光照射15s,用正庚烷洗涤2次,晾干得到布料A;
S2、在布料A表面涂覆20ml含量为9wt%甲基丙烯酸十二氟庚酯的正庚烷溶液,浸润20s,然后用紫外光照射4min,依次用正庚烷、乙醇洗涤2次,然后用水冲洗,于50℃烘干得到布抗污聚丙烯无纺布。
对比例1
纯聚丙烯无纺布,尺寸为15*15cm,克重为70g/m2
实验
将实施例1-3和对比例1,进行性能检测,结果如表1所示。
按照FZ/T60005-1991对各组无纺布进行断裂强力测定。
表1检测结果
Figure BDA0002866068830000051
由上表可以看,本发明具有较低的表面能,具有良好机械性能和抗污性能。
以上所述,仅为本发明较佳的具体实施方式,但本发明的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本发明揭露的技术范围内,根据本发明的技术方案及其发明构思加以等同替换或改变,都应涵盖在本发明的保护范围之内。

Claims (10)

1.一种抗污聚丙烯无纺布,其特征在于,包括基布和粘附在基布表面的抗污层,基布的原料按重量份包括:聚丙烯80-90份、硅烷偶联剂改性二氧化钛10-20份、引发剂0.05-0.1份、相容剂1-2份;抗污层为聚甲基丙烯酸十二氟庚酯层。
2.根据权利要求1所述抗污聚丙烯无纺布,其特征在于,硅烷偶联剂为含不饱和双键的硅烷偶联剂。
3.一种如权利要求1或2所述抗污聚丙烯无纺布的制备方法,其特征在于,包括如下步骤:
S1、在基布表面涂覆二苯甲酮溶液,浸润,然后紫外光照射,洗涤,干燥得到布料A;
S2、在布料A表面涂覆甲基丙烯酸十二氟庚酯溶液,浸润,然后紫外光照射,洗涤,干燥得到布抗污聚丙烯无纺布。
4.根据权利要求3所述抗污聚丙烯无纺布的制备方法,其特征在于,在S1中,紫外光照射10-20s。
5.根据权利要求3或4所述抗污聚丙烯无纺布的制备方法,其特征在于,在S2中,紫外光照射3-5min。
6.根据权利要求3-5任一项所述抗污聚丙烯无纺布的制备方法,其特征在于,浸润时间均≤30s。
7.根据权利要求3-6任一项所述抗污聚丙烯无纺布的制备方法,其特征在于,在S1中,二苯甲酮溶液的浓度为20-30mmol/L。
8.根据权利要求3-7任一项所述抗污聚丙烯无纺布的制备方法,其特征在于,在S1中,二苯甲酮溶液的溶剂为正庚烷。
9.根据权利要求3-8任一项所述抗污聚丙烯无纺布的制备方法,其特征在于,在S2中,甲基丙烯酸十二氟庚酯溶液的含量为8-10wt%。
10.根据权利要求3-9任一项所述抗污聚丙烯无纺布的制备方法,其特征在于,在S2中,甲基丙烯酸十二氟庚酯溶液的溶剂为正庚烷。
CN202011606745.4A 2020-12-28 2020-12-28 一种抗污聚丙烯无纺布及其制备方法 Pending CN112760979A (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011606745.4A CN112760979A (zh) 2020-12-28 2020-12-28 一种抗污聚丙烯无纺布及其制备方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011606745.4A CN112760979A (zh) 2020-12-28 2020-12-28 一种抗污聚丙烯无纺布及其制备方法

Publications (1)

Publication Number Publication Date
CN112760979A true CN112760979A (zh) 2021-05-07

Family

ID=75696312

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011606745.4A Pending CN112760979A (zh) 2020-12-28 2020-12-28 一种抗污聚丙烯无纺布及其制备方法

Country Status (1)

Country Link
CN (1) CN112760979A (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113647290A (zh) * 2021-09-07 2021-11-16 铜陵市国虎生态农业科技有限公司 一种桃果类幼树的改良设施栽培方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101985499A (zh) * 2010-10-28 2011-03-16 浙江工业大学 一种超疏水表面聚丙烯的制备方法
CN109137479A (zh) * 2018-07-10 2019-01-04 安徽玉然经编科技有限公司 一种绷带用丝素蛋白整理的抗污抗菌聚丙烯无纺布的制备方法
CN110885592A (zh) * 2018-09-11 2020-03-17 江苏集萃分子工程研究院有限公司 一种超疏水抗菌阳离子含氟聚合物纳米涂层
CN111395009A (zh) * 2020-05-06 2020-07-10 明光市左方生物科技有限公司 一种耐污型医用涂布无纺布的制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101985499A (zh) * 2010-10-28 2011-03-16 浙江工业大学 一种超疏水表面聚丙烯的制备方法
CN109137479A (zh) * 2018-07-10 2019-01-04 安徽玉然经编科技有限公司 一种绷带用丝素蛋白整理的抗污抗菌聚丙烯无纺布的制备方法
CN110885592A (zh) * 2018-09-11 2020-03-17 江苏集萃分子工程研究院有限公司 一种超疏水抗菌阳离子含氟聚合物纳米涂层
CN111395009A (zh) * 2020-05-06 2020-07-10 明光市左方生物科技有限公司 一种耐污型医用涂布无纺布的制备方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113647290A (zh) * 2021-09-07 2021-11-16 铜陵市国虎生态农业科技有限公司 一种桃果类幼树的改良设施栽培方法
CN113647290B (zh) * 2021-09-07 2023-02-21 铜陵市国虎生态农业科技有限公司 一种桃果类幼树的改良设施栽培方法

Similar Documents

Publication Publication Date Title
US5714257A (en) Silane modified elastomeric compositions and articles made therefrom
CN105862418A (zh) 一种聚丙烯抗菌非织造布的制备方法
CN102492383A (zh) 一种聚烯烃薄膜复合用核壳水性聚氨酯-丙烯酸酯复合乳液胶黏剂的制备方法
CN111485428A (zh) 一种蓄热调温纺织品及其制备方法
WO2012024875A1 (zh) 一种提高定岛超细纤维合成革卫生性能的方法
CN112760979A (zh) 一种抗污聚丙烯无纺布及其制备方法
US20210354428A1 (en) Elastic Silicone Cotton Structure and Preparation Method Thereof
CN1614133A (zh) 溶胶-凝胶抗紫外整理液及其在制备抗紫外织物中的应用
CN113265879A (zh) 一种多重交联超亲水织物及其制备方法
EP1670985A2 (fr) Produit comprenant un support fibreux et un revetement hydrophile et/ou permeabilisant, son procede de preparation et son utilisation
CN114293384B (zh) 一种接枝聚合法制备除甲醛遮阳材料的加工方法
CN112680958B (zh) 一种抗紫外线聚丙烯无纺布及其制备方法
CN106930107B (zh) 包覆无机钛层的uhmwpe复合材料及其制备方法
CN100402748C (zh) 纸质历史文献多功能加固保护胶液
CN114645457B (zh) 一种易于着色且耐老化的无纺布及其制备方法
CN102400376A (zh) 一种丝毛混纺织物的抗皱整理液及其抗皱整理的方法
CN1255601C (zh) 一种制造具有吸湿排汗性织物的方法
CN115748237B (zh) 无氟超疏水材料及其制备方法
CN101885799A (zh) 一种无皂乳液技术制备SiO2/HEMA/MMA杂化材料方法
CN215758215U (zh) 水性超柔服装生态合成革
WO2024000743A1 (zh) 一种防紫外超疏水织物及其制备方法
TWI357452B (zh)
CN110106692A (zh) 一种可增强棉织物撕破强力的免烫整理的方法
CN206765469U (zh) 一种具有聚丙烯编织物面层的纤维增强聚合物毡材及其复合板材
CN112726206A (zh) 一种抗紫外线聚乙烯无纺布及其制备方法

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination